JP2898218B2 - Thermal transfer recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording medium, and more particularly, to a thermal transfer recording medium capable of obtaining a transferred image having a sufficient degree of blackness and having improved runnability.

[0002]

2. Description of the Related Art A thermal transfer recording system uses a thermal transfer recording medium having at least one heat-fusible ink layer provided on a sheet-like substrate, and the thermal transfer recording medium is subjected to heat transfer. This is a recording method in which a fusible ink layer is superposed so as to be in contact with an object to be transferred, and the fusible ink layer is heated and melted by a heating head from the substrate side of the thermal transfer recording medium to obtain a transfer image on the object to be transferred. The thermal transfer recording method has been widely used in recent years because the apparatus to be used has low noise, is excellent in operability and maintainability, and can use plain paper as an object to be transferred.

When recording a transfer image on plain paper or the like using such a thermal transfer recording method, for example, a thermal transfer printer equipped with a thermal head is generally used. However, as the performance of thermal transfer printers has increased, it has become desirable to reduce the thermal energy required for printing as low as possible. The reason for this is that by reducing the thermal energy required for printing to a lower level than before, the heating and cooling cycle time of the head can be shortened, preventing thermal degradation of the head, and in particular, the power supply for line printers can be downsized. It is because it becomes. In addition, it is possible to compensate for the lack of heat resistance of the base material. However, if the melting point of the ink composition is designed to be low in order to keep the heat energy required for printing low, background smearing due to the low melting point component of wax occurs when printing on plain paper, and the fixability of the transferred image and the robustness In addition to the decrease in the property, when the environmental temperature rises during storage, there has been a problem that a so-called blocking phenomenon occurs.

[0004] In order to solve these problems, a resin component is conventionally introduced into a binder of a hot-melt ink layer (Japanese Patent Laid-Open No.
JP-A-4-87234, JP-A-54-163044,
JP-A-56-98269 and JP-A-63-130887), or application of a resin-based overcoat layer to wax ink (JP-A-61-242893). Was not obtained enough to satisfy the balance.

Attempts have also been made to achieve low-energy printing by reducing the thickness of the base material and increasing the heat transfer. However, the problem is that the blackness of the transferred image is reduced, and the runnability of the ink ribbon is reduced. There were problems such as instability.

Further, in an ink ribbon cassette using an ink ribbon made of such a thin thermal transfer recording medium, a drive for assisting the running of the ink ribbon in order to stabilize the running property of the ink ribbon and improve the printing quality. It is necessary to use rollers, and as a result, there is a disadvantage that the number of components increases and the manufacturing cost increases.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a thermal transfer recording medium having good running properties during printing and capable of obtaining a transferred image having a sufficient degree of blackness even in low energy printing.

Another object of the present invention is to provide a thermal transfer recording medium capable of running stably and achieving high print quality even when mounted on an ink ribbon cassette having no drive roller.

[0009]

In order to achieve the above object,
The present inventors have conducted intensive studies and as a result, the physical properties of colorant allowed to contain a heat-meltable ink layer in a specific range and the
It has been found that by including a specific amount of the colorant , a transfer image having a sufficient degree of blackness can be obtained even in low-energy printing, and a thermal transfer recording medium with improved running properties of the ink ribbon can be obtained. .

[0010] The present invention has been made based on the above-described findings. In a thermal transfer recording medium having a base sheet and at least one heat-fusible ink layer provided on the base sheet, the heat-fusible recording medium The ink layer is 10 to 80 nm
Containing carbon black having an oil absorption of less diameter and 60 ml / 100 g, the content of the carbon black
Is 40 to 60 weight per 100 parts by weight of the hot-melt ink layer.
The object has been attained by providing a thermal transfer recording medium characterized in that the thermal transfer recording medium is a mass part .

The present invention is characterized in that a specific amount of carbon black having a specific range of physical property values is contained as a colorant in a heat-fusible ink layer of a thermal transfer recording medium. That is, in the thermal transfer recording medium of the present invention, the heat-fusible ink layer has a particle size of 10 to 80 nm and a size of 60 ml / 100 g.
The carbon black having the following oil absorption is
By containing 40 to 60 parts by weight in 100 parts by weight of the ink layer, it is possible to obtain a transferred image having a sufficient degree of blackness even in low energy printing, and
Drivability is also improved. The thermal transfer recording medium of the present invention,
It is particularly useful to use it in the form of an ink ribbon.

Hereinafter, the thermal transfer recording medium of the present invention will be described in detail.

As described above, the thermal transfer recording medium of the present invention
A particle diameter of 10 to 80 nm and a particle diameter of 60
A carbon black having an oil absorption of not more than 100 ml / 100 g is added to 100 parts by weight of the hot-melt ink layer.
The content is within the range of parts by weight . First, the carbon black contained in the hot-melt ink layer will be described.

The above carbon black is used as a coloring agent in the thermal transfer recording medium of the present invention.
As long as the particle diameter and the oil absorption are within the above ranges, they can be used without particular limitation. For example, furnace black obtained by a pyrolysis method or an incomplete combustion method,
Various carbon blacks such as lamp black, thermal black, acetylene black and channel black, conductive carbon blacks and the like can be used.

The carbon black has a particle size of 1
0 to 80 nm. If the particle size is less than 10 nm, the viscosity of the ink paint will increase, the resolution of the transferred image will decrease, and the runnability will deteriorate. If the particle size exceeds 80 nm, the dispersibility of the ink paint will deteriorate and the blackness will decrease. This causes an increase in voids in the black solid coating. The particle size refers to a primary particle size of the carbon black, and can be measured by, for example, an electron microscope. The particle size is 20
It is preferably from 50 to 50 nm, more preferably from 20 to 30 nm.

The carbon black has an oil absorption of 60 ml / 100 g or less. The oil absorption is 60 ml /
If it exceeds 100 g, the viscosity of the ink paint will increase, the resolution of the transferred image will decrease, and the running property will deteriorate. In addition,
The oil absorption is determined by DBP (dibutyl phthalate method) (AS
TM D2414-65T). The oil absorption is preferably 5 to 60 ml / 100 g, and more preferably 10 to 60 ml / 100 g.

As described above, in the thermal transfer recording medium of the present invention, the carbon black has a particle diameter and an oil absorption in the above ranges.
It is also preferable that the coloring power index and the apparent density are in the following ranges.

That is, the carbon black preferably has a specific surface area of 25 to 300 m ² / g. If the specific surface area is less than 25 m ² / g, dispersibility in the ink paint may be deteriorated, blackness may be reduced, and voids may be increased at the time of black solid coating.
If it exceeds 0 m ² / g, the viscosity of the ink paint may be increased, the resolution of the transferred image may be reduced, and the running property may be deteriorated. The specific surface area is a value measured by a nitrogen adsorption (BET method) method. The specific surface area, more preferably from 30~250m ² / g, and still more preferably 40 to 150 m ² / g.

Further, the carbon black preferably has a coloring power index of 125 or less. When the coloring power index exceeds 125, an ink paint having good dispersibility cannot be obtained, or the resolution of a transferred image is reduced,
Since the traveling performance may be deteriorated, it is preferable to set it to 125 or less. The coloring power index refers to an ASTM N under conditions where the coloring power of standard black is 100.
This is a value measured at -440. The coloring power index is 0
More preferably from 120 to 120, and still more preferably from 30 to 100.

Further, the carbon black preferably has an apparent density of 200 to 400 g / cm ³ . If the apparent density is less than 200 g / cm ³ , the dispersibility of the ink paint may be deteriorated, the blackness may be reduced, or voids may be increased at the time of black solid coating, and may exceed 400 g / cm ³ . In some cases, the viscosity of the ink paint may increase, the resolution of the transferred image may be reduced, and the running property may be deteriorated. The apparent density can be measured, for example, from the weight when the carbon black is filled in a container having a fixed capacity. The apparent density is 200 to 350 g / c.
more preferably m ^3, 250~350g / c
m ³ is more preferable.

The carbon black is contained in an amount of 40 to 60 parts by weight based on 100 parts by weight of the hot-melt ink layer.
Or blackness decreases the content of the carbon black is small, there Ru when the running resistance is deteriorated.

If necessary, the heat-meltable ink layer may contain another coloring agent in addition to the carbon black for the purpose of, for example, multicolor printing. Examples of such other colorants include black dyes and pigments such as oil black and graphite; I. Pigment Yellow 1, 3, and 7
C. 4, 97, 98 etc. acetoacetic acid arylamide type monoazo yellow pigment (fast yellow); I. C.I. Pigment Yellow 12, 13, and 14 and the like. I. Solvent Yellow 19, 77, 79, C.I. I. Disperse
Yellow dyes such as yellow 164; I. Pigment Red 8, 49: 1, 53: 1, 57: 1, 81
Red pigments such as 122 and 5; C.I. I. Red dyes such as Solvent Red 52, 58 and 8; C.I. I. Pigment Blue 15: 3, etc., copper phthalocyanine and its derivatives, modified dyes and the like can be used, and colored or colorless sublimable dyes, conventional printing inks, and other well-known dyes and pigments for coloring purposes can be used. These dyes and pigments may be used alone or in combination of two or more. Of course, the color tone may be adjusted by mixing with an extender or a white pigment. The other colorant is based on 100 parts by weight of the carbon black.
It is preferable to use 0 to 20 parts by weight. Furthermore, the surface of the colorant is treated with a surfactant, a coupling agent such as a silane coupling agent, a polymer material, or a polymer dye or a polymer graft pigment to improve dispersibility in the binder. You may.

Next, the hot-melt ink layer containing the carbon black will be described. The heat-meltable ink layer contains the carbon black and the binder, is softened and melted by heating, and is transferred to a transfer-receiving body. The heat-meltable ink layer is provided at least one layer on a base sheet described later.

As the binder, a substance usually used for a hot-melt ink layer can be used without any particular limitation, and the melt viscosity at 100 ° C. is 2,50.
It is desirable to use a binder of 0 to 200,000 cP. The binder is preferably blended in an amount of 100 to 900 parts by weight based on 100 parts by weight of the carbon black.

Particularly preferred as the binder is an isocyanate polymer of a higher fatty acid polyhydric alcohol ester. In particular, the melt viscosity at 100 ° C. is 2,50.
0 to 50,000 cP (particularly 4,000 to 20,000 cP)
Those of cP) are preferred. The above melt viscosity is 2,500c
If it is less than P, the cohesive force is weak similarly to the wax, and it may be difficult to form a uniform transfer image.
If the value exceeds P, the cut of the ink is poor and a transferred image having poor resolution is obtained.

The isocyanate polymer of the higher fatty acid polyhydric alcohol ester is obtained by adding an isocyanate compound to an esterified product of a higher fatty acid and a polyhydric alcohol.

As the higher fatty acid for obtaining the higher fatty acid polyhydric alcohol ester, saturated fatty acid, unsaturated fatty acid, alicyclic fatty acid, oxygen-containing fatty acid, hydroxy fatty acid and the like can be used. The number of carbon atoms is 2 to 60, preferably 5 to 50, and particularly preferably 10 to 40. In the present invention, particularly, a fatty acid having a melting point of 20 ° C. or more and a carbon number of 10 to 40 can be suitably used, for example, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid,
Saturated fatty acids such as palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachiic acid, behenic acid, lignoceric acid, serotinic acid, heptacosanoic acid, montanic acid, melicic acid, and lacceric acid; acrylic acid, crotonic acid,
Isocrotonic acid, caproleic acid, undecylenic acid, oleic acid, elaidic acid, setleic acid, erucic acid, brassic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, succinic acid, nisinic acid, propiolic acid, stearolic acid, etc. Unsaturated fatty acids; branched fatty acids such as isovaleric acid, malvaric acid, sterculinic acid,
Alicyclic fatty acids such as hydnocarbic acid, shorum-gulic acid, and gorlic acid; oxygen-containing fatty acids such as sabinic acid, iprolic acid, yarapinolic acid, uniperic acid, ricinoleic acid, and cerebronic acid; and hydroxy fatty acids such as 12-hydroxystearic acid; Can be used. Among them, lanolin fatty acids obtained by degrading lanolin secreted from the sebaceous glands of sheep by ken value are most effective. These fatty acids may be used alone or in combination of two or more.

As the polyhydric alcohol for obtaining the above-mentioned higher fatty acid polyhydric alcohol ester, saturated aliphatic polyols, unsaturated aliphatic polyols, alicyclic polyols, oxygen-containing aliphatic polyols and the like can be used. The polyol has a carbon number of 1 to 50, preferably 1 to 20, and particularly preferably 2 to 10. In the present invention, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, trimethylene glycol, butanediol,
Pentanediol, hexylene diol, octylene diol, glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, 1,3-butylene glycol, glycerin monoallyl, [4- (hydroxyethoxy) phenol] propane, sorbitol, sorbitol, Neopentyl glycol, trishydroxyethyl isocyanurate, bisphenol, hydrogenated bisphenol, bisphenol glycol ether,
Various epoxy group-containing compounds (for example, triglycidyl isocyanurate) and the like are used. These polyhydric alcohols may be used alone or in combination of two or more.

As the isocyanate compound to be added to the higher fatty acid polyhydric alcohol ester, monoisocyanate, diisocyanate, triisocyanate and the like can be used.
Ethyl isocyanate, n-propyl isocyanate,
monoisocyanates such as n-butyl isocyanate, octadecyl isocyanate, and polymethylene polyphenyl isocyanate; 2,4-tolylene diisocyanate;
4,4′-diphenylmethane diisocyanate, dianisidine diisocyanate, metaxylylene diisocyanate, 1,5-naphthalenediisocyanate, trans vinylenediisocyanate, N, N ′ (4,4′-dimethyl-3,3′-diphenyl diisocyanate) uridine, Diisocyanates such as 2,6-diisocyanate methylcaproate; triphenylmethane triisocyanate, tris (4-phenylisocyanate thiophosphate) 4,4 ′, 4 ″ -trimethyl-3,3 ′,
And triisocyanates such as 3 "-triisocyanate-2,4,6-triphenylcyanurate. Particularly preferred are diisocyanates and triisocyanates, and more preferably aromatic ones. The compounds may be used alone or in combination of two or more.

The esterification reaction between the higher fatty acid and the polyhydric alcohol can be carried out by any conventionally known method. The degree of esterification is not particularly limited. The addition reaction between the higher fatty acid polyhydric alcohol ester prepared according to the above method and the isocyanate compound can be carried out according to a conventionally known method. The number of moles of the isocyanate compound added is not particularly limited, but is preferably about 0.1 to 5 moles per mole of the higher fatty acid polyhydric alcohol ester. In addition, as the isocyanate adduct of the higher fatty acid polyhydric alcohol ester, a commercially available product can also be used. For example, Lanox FPK-210 manufactured by Yoshikawa Oil Co., Ltd. can be used.

The isocyanate polymer of the higher fatty acid polyhydric alcohol ester may be used in combination with other binders,
It is particularly preferred to use with a vinyl acetate copolymer. The ethylene-vinyl acetate copolymer has a melt flow rate of 5 to 2000 dg / min (particularly 5 to 2000 dg / min).
(1000 dg / min) is particularly preferred. If the melt flow rate is less than 5 dg / min, the cut of the ink is poor, and a transfer image having poor resolution may be obtained.
If it exceeds 2,000 dg / min, ink flow or the like may occur, and normal and uniform thermal transfer recording may not be performed.

The ethylene-vinyl acetate resin is preferably blended in an amount of 5 to 900 parts by weight based on 100 parts by weight of the isocyanate polymer of the higher fatty acid polyhydric alcohol ester. If the amount is less than 5 parts by weight, problems such as background contamination may occur. If the amount is more than 900 parts by weight, the transferred image lacks abrasion resistance, sensitivity is reduced, and high-speed printing is difficult. The resolution may be lowered, so that it is preferable to be within the above range.

Further, another binder may be added to the hot-melt ink layer, if necessary. As the binder to be added, styrene such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, vinylbenzoic acid, sodium vinylbenzenesulfonate, aminostyrene, and derivatives and substituted homopolymers and copolymers thereof may be used. Can be used. Further, methacrylic acid esters and methacrylic acid such as methyl methacrylate, ethyl methacrylate, butyl methacrylate and hydroxy methacrylate; acrylic acid esters and acrylic acid such as methyl acrylate and 2-ethylhexyl acrylate; dienes such as butadiene and isoprene; acrylonitrile;
Vinyl ethers, maleic acid and maleic acid esters, maleic anhydride, cinnamic acid, vinyl monomers such as vinyl chloride, and the like or copolymers with other monomers can also be used. Of course, in the case of the vinyl polymer, a polyfunctional monomer such as divinylbenzene may be used as a crosslinked polymer. Further, polycarbonate, polyester, silicone resin, fluorine resin, phenol resin, tempen resin, petroleum resin, hydrogenated petroleum resin, alkyd resin, ketone resin, cellulose derivative and the like may be used. When these polymers or oligomers are used in the form of a copolymer, the copolymer may be a random copolymer, an alternating copolymer, a block copolymer or an interpenetrating copolymer, depending on the required application. Etc. can be appropriately selected and used. When two or more kinds of polymers and oligomers are mixed and used, in addition to mechanical mixing such as melt mixing, solution mixing, and emulsion mixing, they are mixed by coexisting polymerization or multi-stage polymerization during polymerization of polymers and oligomer components. May be. The other binder is 100 parts by weight of the carbon black.
It is preferable to mix up to parts by weight.

Further, if necessary, waxes, oils, (liquid) plasticizers, or resins as used for the heat-fusible substance in the conventional thermal transfer recording medium are added to the heat-fusible ink layer. You may. In addition, ethylene, olefin homopolymer or copolymer such as propylene, organic acid graft olefin copolymer, chlorinated paraffin, low molecular urethane compound, plasticizer solid at room temperature,
A charge controlling and / or preventing agent such as a surfactant, a conductive agent, an antioxidant, a thermal conductivity improver, a magnetic substance, a strong derivative,
Preservatives, fragrances, antiblocking agents, reinforcing fillers, release agents, foaming agents, sublimable substances, infrared absorbers, and the like may be added to the hot-melt ink layer or other layers.

The thickness of the heat-fusible ink layer is not particularly limited, but is preferably about 0.1 to 10 μm,
More preferably, it is less than 5.0 μm.

Next, the base sheet provided with the above-mentioned hot-melt ink layer will be described. As the material of the base sheet, a material having heat resistance, high dimensional stability and high surface smoothness is preferable. More specifically, in addition to paper and polyethylene terephthalate, such as condenser paper, glassine paper and synthetic paper, which have been mainly used as a base sheet of a thermal transfer recording medium, polycarbonate, polyethylene,
Thin film sheets and films of resin films such as polystyrene, polypropylene, polyimide and polyamide are used. The thickness of the base sheet is not particularly limited, but is preferably in the range of about 0.5 to 20 μm, and more preferably in the range of 0.5 μm to less than 3.0 μm.

The thermal transfer recording medium of the present invention preferably has a release layer between the base sheet and the hot-melt ink layer. Such a release layer improves the releasability of the hot-melt ink layer. As a result, transfer sensitivity is improved,
In addition, the running property of the ink ribbon is further improved.

The release layer contains a wax component.
The type of the wax component is not particularly limited as long as it has releasability. For example, polyethylene wax, paraffin wax, rice bran wax, microcrystalline wax, carnauba wax, shellac wax, montan wax, higher fatty acids, higher fatty acid amides and higher alcohols can be used. The wax components may be used alone or in combination of two or more. In particular, it is preferable that the release layer contains one or more wax components selected from the group consisting of polyethylene wax and paraffin wax. Especially, it is desirable to use polyethylene wax in view of the running property of the ink ribbon during low energy printing.

Examples of the polyethylene wax include those produced by polymerization of ethylene, those obtained by a method of reducing the molecular weight of polyethylene for general molding by thermal decomposition, and those produced as by-products when producing polyethylene for general molding. And those obtained by oxidizing polyethylene for general molding, and the like. Above all, from the viewpoint that the particle size distribution can be adjusted to a narrow range, those obtained by a method of polymerizing under a high temperature and a high pressure with a radical catalyst or a method of polymerizing at a low pressure with a Ziegler catalyst are preferable.

Commercially available products can also be used as the polyethylene wax. Examples of such commercially available products include Mitsui High Wax (Mitsui Petrochemical Industries), A-Wax (BA
SF), AC-polyethylene (Allied Signal), Epolen (Eastman Chemical), Hoechst wax (Hoechst), Sunwax (Sanyo Chemical), Baleco wax (Baleco) and Sasol wax (Sasol) ), Polywax (Toyo Petrolite).

The above wax component preferably has a melt viscosity at 100 ° C. of less than 15 cP. 1
If the melt viscosity at 00 ° C. is 15 cP or more, the runnability of the thermal transfer recording medium may decrease due to an increase in the peeling force during printing. The melt viscosity of the wax component generally depends on its molecular weight and density. The melt viscosity of the wax component is more preferably less than 12 cP, more preferably less than 7 cP.

In particular, the wax component contained in the release layer preferably has a melt viscosity at 100 ° C. of less than 15 cP and a drop point based on ASTM D-3104 of 100 ° C. or less. If the dropping point is higher than 100 ° C., the running force of the ink ribbon may be affected by an increase in the peeling force during low energy printing. More preferably, the drop point is 98 ° C. or lower.

Further, in order to improve the coating strength and flexibility of the release layer, ethylene-vinyl acetate copolymer and ethylene-acrylic acid copolymer may be used as long as the effects of the present invention are not impaired. Resins such as polymers, polyethylene and petroleum resins may be added. These resins may be used alone or in combination of two or more.

The mixing ratio of the wax component and the resin contained in the release layer is not particularly limited, but the mixing ratio of the wax component as a general range is preferably 1% in the release layer. To 100% by weight, more preferably 20 to 99% by weight.
In the release layer, the content is preferably 0 to 50% by weight, more preferably 1 to 20% by weight.

The thickness of the release layer is not particularly limited,
Generally, the thickness is preferably 0.1 μm or more and less than 5.0 μm, and particularly preferably 0.1 or more and less than 3.0 μm. This is because if the thickness of the release layer is within this range, the transfer sensitivity is improved due to a decrease in the release force.

When the thickness of the release layer is 0.1 μm or more and less than 3.0 μm and the thickness of the base sheet is 0.5 μm or more and less than 3.0 μm, which is thinner than usual, a more satisfactory blackness Is obtained, and the running stability is further improved.

In particular, the thickness of the release layer is 0.1 μm or more and less than 5.0 μm, the thickness of the substrate sheet is 0.5 μm or more and less than 3.0 μm, which is thinner than usual, and Is particularly preferable when the thickness is 0.1 μm or more and less than 5.0 μm, which is smaller than usual, since a transferred image having a still more satisfactory blackness degree can be obtained and the running stability is further improved. In particular, the present invention is effective when the thermal transfer recording medium of the present invention is used as an ink ribbon in an ink ribbon cassette described later, and the ink ribbon is run at high speed.

Further, in the thermal transfer recording medium of the present invention,
In order to reduce the peeling force of the release layer, it is preferable that the melt viscosity of the release layer at 100 ° C. is higher than the melt viscosity of the hot melt ink layer at 100 ° C.

Further, in the thermal transfer recording medium of the present invention, heat resistance and running property are further improved on the surface of the base sheet opposite to the surface on which the heat-fusible ink layer is provided. A back coat layer may be provided.
Such a back coat layer is particularly advantageous when a thermal head is used as a heat source for thermal transfer.

The back coat layer generally comprises a nitrocellulose-based, silicone-based or fluorine-based compound.
Preferably, the back coat layer is formed of a reaction product of an aminosilicone resin (for example, a silicone oil obtained by introducing an amino group into a part of the methyl group of dimethylpolysiloxane) and a polyfunctional isocyanate (for example, TDI) or a silicone resin. It consists of butyral resin. Generally, the thickness of the back coat layer is preferably 0.01 to 0.5 μm, but is not limited to this range.

Further, in the thermal transfer recording medium of the present invention, an overcoat layer, a resistance layer for energization and heating, etc. may be provided.

Next, a preferred method for producing the thermal transfer recording medium of the present invention will be described.

To produce the thermal transfer recording medium of the present invention,
First, the above-mentioned wax component and the like are applied on the above-mentioned base sheet as necessary to form a release layer.

The method for applying the wax component and the like on the base sheet is not particularly limited, and examples thereof include a method of applying with a wire coater.

Next, a hot-melt ink is applied on the base sheet or on the base sheet on which the release layer is formed to form a hot-melt ink layer.

The hot-melt ink coating composition is prepared by dissolving or stably dispersing the binder in a solvent or a dispersion medium in the form of a solution or a dispersion emulsion, and using a ball mill, sand mill, attritor, dyno mill, three roll It can be performed by a mixing and dispersing machine. Further, after the carbon black is dispersed by the above-described method, fine particles may be added and the mixture may be stirred and mixed by a homomixer, a disper, a dissolver, or the like. Further, the mixture may be melt-mixed with a three-roll, kneader, sand mill, attritor or the like without using a solvent or the like.

The hot-melt ink paint thus prepared is applied to the above-mentioned base sheet or the above-mentioned base sheet on which the release layer is formed by a solution or melt coating method using a gravure coater, a wire bar or the like. Is printed. Alternatively, the hot-melt ink paint may be pulverized by a spray drying method, and then powder-coated on the base sheet or the release layer by an electrostatic coating method or the like. in this case,
After the powder coating, if necessary, heating, pressurizing, solvent treatment, or the like may be performed to fix the hot-melt ink coating on the base sheet or the release layer before use.

Next, an ink ribbon cassette provided with the thermal transfer recording medium of the present invention will be described with reference to the drawings. Here, FIG. 1 is a plan view showing an aspect of the ink ribbon cassette in which the drive roller is not provided, and the inner surface of the lower half is omitted while the upper half is omitted. FIG. 2 is a view in which the drive roller is provided. FIG. 6 is a plan view showing an aspect of the ink ribbon cassette in which the upper half is omitted and the inner surface of the lower half is viewed.

First, the ink ribbon cassette shown in FIG. 1 where no drive roller is provided will be described. FIG.
The ink ribbon cassette shown in (1) is provided with the thermal transfer recording medium of the present invention as an ink ribbon, and has no drive roller. Generally, when the thickness of the ink ribbon is thinner than usual, a driving roller for assisting the running of the ink ribbon is provided in the ink ribbon cassette in order to stabilize the running property of the ink ribbon. When the thermal transfer recording medium of the present invention is used as an ink ribbon, even in an ink ribbon cassette not using the drive roller, the running property of the ink ribbon is sufficiently stable, and a transfer image having a sufficient degree of blackness is obtained. can get.

In the ink ribbon cassette shown in FIG. 1, a pair of take-up hubs around which an ink ribbon is wound and a supply hub are housed in a cassette body composed of an upper half and a lower half.
The ink ribbon is stretched through a plurality of guide rollers or guide pins provided in the cassette, and a print head insertion recess is provided at a front end of the cassette. The ink ribbon cassette is not provided with a drive roller for assisting the travel of the ink ribbon. Further, the thermal transfer recording medium of the present invention is used as the ink ribbon.

That is, the ink ribbon cassette shown in FIG. 1 has a pair of take-up hubs 31 and supply hubs 32 around which the ink ribbons 2 are wound in a cassette body composed of an upper half (not shown) 11 and a lower half 12. At the front end of the cassette body, a head unit 4 for running the ink ribbon 2 led out, and five guide rollers 65, 66 for guiding the running of the ink ribbon 2;
67, 68 and 69 are provided. Guide roller 6
5, 66, 67, 68, and 69 are preferably made of plastic from the viewpoint of preventing the ink ribbon from getting caught.

In the ink ribbon cassette 1 shown in FIG. 1 configured as described above, the ink ribbon 2 is pulled out from the supply hub 32 toward the guide roller 65 as shown in FIG. After being inverted by the guide roller 65, the guide roller 66 is guided to the head unit 4 via the guide rollers 66 and 67, travels through the head unit 4, is returned into the cassette body via the guide roller 68, and The traveling path is formed such that the roller is inverted by the roller 69 and wound around the winding hub 31. The ink ribbon cassette 1
Are reversible.

Next, a description will be given of the ink ribbon cassette shown in FIG. Note that FIG.
In the following description, the same points as those in FIG. 1 are not described in detail, but the description in detail with reference to FIG. 2, the same members as those in FIG. 1 are denoted by the same reference numerals.

The ink ribbon cassette shown in FIG. 2 is characterized in that the thermal transfer recording medium of the present invention is provided as an ink ribbon and a drive roller is provided. As described with reference to FIG. 1, in the ink ribbon cassette including the thermal transfer recording medium of the present invention as the ink ribbon, the ink ribbon can run satisfactorily without using a driving roller that assists the ink ribbon to run. When the driving roller is used, the running of the ink ribbon is further stabilized.

In the ink ribbon cassette 1 shown in FIG. 2, a pair of a take-up hub 31 and a supply hub 32 around which the ink ribbon 2 is wound are housed in a cassette body composed of an upper half (not shown) 11 and a lower half 12. At the front end of the cassette main body, there is provided a head 4 for running the ink ribbon 2 led out to the outside, and the winding hub 31 is provided between the head 4 and the winding hub 31. A drive roller 51 for assisting the travel of the ink ribbon 2 wound around the ink ribbon 2 is provided, and four guide rollers 61, 62, 63, 64 for guiding the travel of the ink ribbon 2 are provided.
The guide roller 6 which is one of the guide rollers
1 is disposed between the drive roller 51 and the take-up hub 31 in the vicinity of the drive roller 51, and the guide roller 61 applies the ink ribbon 2 to the surface of the drive roller 51. After being brought into contact with the semi-peripheral surface or more, it is arranged so as to be brought into contact with the opposite side of the contact surface with the drive roller 51 to be guided to the winding hub 31.

In the ink ribbon cassette 1 described above,
The drive roller 52 is provided between the head unit 4 and the supply hub 3.
2, and the guide roller 64 is disposed between the drive roller 52 and the supply hub 32 in the vicinity of the drive roller 52.

As shown in FIG. 2, the driving roller 51 is provided in the vicinity of a corner at the front end of the take-up hub 31 with respect to the head portion 4, and includes the upper half 11 and the lower half. The ink ribbon cassette 1 is rotatably fitted into a support hole provided in the half 12, and is connected to a driving source (not shown) for driving when the ink ribbon cassette 1 is used, and is wound around the winding hub 31. The travel of the ink ribbon 2 is assisted.

When the ink ribbon cassette 1 is used so that the driving roller 51 functions as described above, the driving roller 52 on the supply hub 32 side is not connected to a driving source, but is connected to the ink ribbon 2. It functions as a tension applying roller for applying tension, and stabilizes the pulling tension of the ink ribbon 2 from the supply hub 32. The roller surfaces 51a and 52a of the drive rollers 51 and 52 are preferably made of plastic, not rubber, from the viewpoint of preventing the ink ribbon 2 from getting caught.

The guide rollers 61, 62, 63, 64
As shown in FIG. 2, the guide roller 61 is disposed between the winding hub 31 and the drive roller 51, the guide rollers 62 and 63 are disposed between the drive rollers 51 and 52, and the guide roller Numerals 64 are located between the supply hub 32 and the drive roller 52, respectively, and rotatably fitted into support pins 7, 7 provided on the inner side surfaces of the upper half 11 and the lower half 12, respectively. The ink ribbon 2 is guided from the supply hub 32 to the winding hub 31 by traveling along the head portion 4.

In the ink ribbon cassette 1 shown in FIG. 2 configured as described above, a traveling path similar to that of the ink ribbon cassette shown in FIG. 1 is formed except that the driving rollers 51 and 52 are used. The ink ribbon cassette shown in FIG. 2 can be used in the same manner as the ink ribbon cassette shown in FIG. 1, and when the ink ribbon cassette is used in the reverse direction, the drive roller 52 is positioned on the winding side and connected to the drive source. The driving roller 51 functions in the same manner as the driving roller 51, and the driving roller 51 is located on the supply side and functions as a tension applying roller in the same manner as the driving roller 52. Further, the roller surface 52a has the same function as the roller surface 51a. Works.

In the ink ribbon cassette shown in FIGS. 1 and 2, preferably, the friction coefficient (μ) between the ink ribbon 2 and the roller surfaces 65a to 69a of the guide rollers 65 to 69 or the ink ribbon 2 and the driving roller 5
Coefficient of friction (μ) between rollers 1 and 52 with roller surfaces 51a and 52a
Is 0.1 to 1.4. By setting the coefficient of friction (μ) within the above range, the ink ribbon is less likely to be caught by the guide roller and the drive roller during running of the ink ribbon, and is more smoothly wound on the winding hub. When the friction coefficient (μ) is less than 0.1, the ink ribbon slides on the roller surface of the guide roller or the drive roller, and the driving force decreases. When the friction coefficient (μ) exceeds 1.4, the ink ribbon deforms such as wrinkles. May occur or the ink ribbon may be entangled in the guide roller or drive roller.
It is preferable to be within the above range. Above friction coefficient (μ)
Is more preferably 0.1 to 1.2.

In the ink ribbon cassette shown in FIGS. 1 and 2, preferably, the guide rollers 65 to 6 are used.
9, the roller surfaces 65a to 69a or the driving roller 51,
52, the Shore A hardness of the roller surfaces 51a, 52a is 55
~ 98. By setting the Shore A hardness within the above range, adhesion between the ink ribbon and the roller surfaces of the guide roller and the driving roller is eliminated, and the running stability of the ink ribbon is further improved. If the Shore A hardness is less than 55, the ink ribbon adheres to the roller surface of the guide roller or drive roller, and the running stability of the ink ribbon decreases. If the Shore A hardness exceeds 98, the ink ribbon easily slips upward. , Within the above range. A more preferred range of the Shore A hardness is 80 to 98. The Shore A hardness can be measured by, for example, a Shore hardness tester (TYPE A) manufactured by TEC LOCK.

In the ink ribbon cassette shown in FIG. 2, the winding angle θ of the ink ribbon 2 around the drive rollers 51 and 52 is preferably 0 to 270 °.
By setting the winding angle θ within the above range, the ink ribbon is guided by the guide roller and is wound on the winding hub more smoothly without being wound on the drive roller or the like while the ink ribbon is running. Can be If the winding angle θ exceeds 270 °, the ink ribbon may be entangled in the drive roller and may not be able to run, so it is preferable to be within the above range. A more preferable range of the winding angle θ is 5 to 225 °.

Further, in the ink ribbon cassette shown in FIG. 1, a) the requirement of using a plastic guide roller, b) the coefficient of friction (μ) between the ink ribbon and the roller surface of the guide roller is 0.1-1. It is also preferable to satisfy any two of the requirements that the roller surface of the guide roller has a Shore A hardness of 55 to 98, and more preferably the requirements of the above a) to c). Have all the requirements.

Further, in the ink ribbon cassette shown in FIG. 2, d) the requirement of using a plastic drive roller, and e) the friction coefficient (μ) between the ink ribbon and the roller surface of the drive roller is 0.1 to 1. Requirement of 4) f)
Shore A hardness of the roller surface of the drive roller is 55 to 9
8), and g) any two of the requirements that the winding angle θ of the ink ribbon around the drive roller is 0 to 270 °, and more preferably the above d) to d). It has any three of the requirements g), and particularly preferably has all of the above d) to g).

Further, in the ink ribbon cassette shown in FIGS. 1 and 2, the thermal transfer recording medium of the present invention is used as the ink ribbon, and the thickness of the base sheet in the thermal transfer recording medium is set to be smaller than normal. 0.5 μm or more and less than 3.0 μm, and the thickness of the release layer is 0.1 μm
The thickness of the hot-melt ink layer is preferably 0.1 μm or more and less than 5.0 μm, which is thinner than usual, in terms of the running property of the ink ribbon.
The thickness of the base sheet is set to 0.5 μm or more and less than 3.0 μm, which is thinner than usual, and the thickness of the release layer is set to 0.1 μm.
It is particularly effective to set the thickness to less than 5.0 μm.

[0077]

EXAMPLES Hereinafter, the present invention will be described in more detail, but the present invention is not limited to these examples. In the following description, parts mean parts by weight unless otherwise specified.

Example 1 Paraffin wax (HNP)
-10; made by Nippon Seiro, melt viscosity at 100 ° C; 8c
P, dropping point based on ASTM D-3104; 75 ° C) 9
5 parts and 5 parts of an ethylene-vinyl acetate copolymer were dispersed in a toluene solvent using a ball mill to prepare a coating for a release layer. Then, this release layer paint is applied on a 2.5 μm thick PET film (base sheet) coated with a silicone-based back coat using a wire bar coater to form a 1.0 μm thick release layer. Provided.

Next, the following components were charged into a toluene solvent at a solid content of 20% by weight, and dispersed in a ball mill for 20 hours to prepare a hot-melt ink. Then, the obtained hot-melt ink is applied on the release layer using a wire bar coater, and dried to obtain only a solid content, and has a thickness of 2 μm.
Thus, a target thermal transfer recording medium having a m.

40 parts of carbon black (Raven-1200, manufactured by Columbia, particle diameter: 24 nm, oil absorption: 60 ml / 100 g, specific surface area: 120 m ² / g, coloring power index: 125, apparent density: 240 g / cm ³・ Ethylene vinyl acetate copolymer EV260 (5 dg / min) 30 parts ・ Isocyanate polymer of lanolin fatty acid polyhydric alcohol ester (melt viscosity at 100 ° C .: 5000 cP) 30 parts ・ Toluene (solvent) 400 parts

The thus-obtained thermal transfer recording medium was slit to a width of 12.7 mm to obtain an ink ribbon.
This ink ribbon was incorporated in the ink ribbon cassette shown in FIG. The ink ribbon cassette is provided with a plastic guide roller. The coefficient of friction (μ) between the ink ribbon and the roller surface of the guide roller was 0.15, and the Shore A hardness of the roller surface of the guide roller was 70. The ink ribbon cassette was printed on plain paper (BEKK smoothness: 160 seconds) using a serial thermal transfer printer (FW-U1P95 360 DPI, manufactured by Matsushita Electric Industrial Co., Ltd.), and the blackness of the transferred image was measured. To investigate the relationship between printing energy and blackness, operate the density adjustment lever to change the applied voltage between 30.0-36.5V, and measure the blackness of the transferred image with a Macbeth densitometer (RD514 type). did.
As a result, the applied voltage required to obtain a transfer image having a density of 1.2 was 31.5 V. No background stain was observed at the time of printing. The running property of the ink ribbon was good.

Example 2 Low molecular polyethylene wax (polywax 655; manufactured by Toyo Petrolite, 100 ° C.)
Melt viscosity at 6 cP, dropping point based on ASTM D-3104; 87 ° C), and a release layer formed from 95 parts of an ethylene-vinyl acetate copolymer, and the following carbon black was used. Except for the above, the same operation as in Example 1 was performed to produce a thermal transfer recording medium.・ Carbon black (made by Columbia; RAVEN-10)
20, particle diameter: 27 nm, oil absorption: 60 ml / 100 g,
Specific surface area: 95 m ² / g, coloring power index: 121, apparent density: 270 g / cm ³ ) The thus obtained thermal transfer recording medium is 12.7 m wide.
m to obtain an ink ribbon. This ink ribbon was incorporated in the ink ribbon cassette shown in FIG.
The ink ribbon cassette is provided with a plastic driving roller. The coefficient of friction (μ) between the ink ribbon and the roller surface of the drive roller is equal to 0.1.
The Shore A hardness of the roller surface of the drive roller was 70, and the winding angle θ of the ink ribbon around the drive roller was 170 °. The same printing as in Example 1 was attempted on the ink ribbon cassette. Macbeth densitometer (RD514 type)
As a result, the applied voltage required to obtain a transfer image having a density of 1.2 was 32.0 V. The running property of the ink ribbon was good.

Example 3 Candelilla Wax (Special No .; Noda Wax, melt viscosity at 100 ° C .; 1)
4 cP, dropping point based on ASTM D-3104; 72
° C) using the release layer formed from 95 parts and 5 parts of an ethylene-vinyl acetate copolymer, and performing the same operation as in Example 1 except that the following was used as carbon black.
A thermal transfer recording medium and an ink ribbon cassette were prepared and printing was attempted. Measure the blackness of the transferred image with a Macbeth densitometer (RD5
As a result, the applied voltage required to obtain a transferred image having a density of 1.2 was 31.0 V. The running property of the ink ribbon was good.・ Carbon black (made by Columbia; RAVEN-10)
35, particle diameter: 27 nm, oil absorption: 60 ml / 100 g,
Specific surface area: 95 m ² / g, coloring power index: 123, apparent density: 240 g / cm ³ )

[Comparative Example 1] Candelilla wax (special special number; manufactured by Noda Wax, melt viscosity at 100 ° C; 1)
4 cP, dropping point based on ASTM D-3104; 72
C) using a release layer (1 μm thick) formed of 95 parts and 5 parts of ethylene-vinyl acetate copolymer.
The same operation as in Example 1 was performed except that the thickness of the film (base sheet) was 2 μm, the thickness of the heat-fusible ink layer was 2 μm, and the following was used as carbon black, And an ink ribbon cassette were prepared and printing was attempted. As a result of measuring the blackness of the transferred image with a Macbeth densitometer (RD514 type), the applied voltage required to obtain a transferred image having a density of 1.2 was 35.5 V. In addition, the running property of the ink ribbon was unstable, especially immediately after the start of printing.・ Carbon black (made by Degussa; Lamp Black 101,
Particle size: 95 nm, oil absorption: 112 ml / 100 g, specific surface area: 20 m ² / g, coloring power index: 29, apparent density;
260 g / cm ³ )

Comparative Example 2 Paraffin wax (HNP)
-10; made by Nippon Seiro, melt viscosity at 100 ° C; 8c
P, dropping point based on ASTM D-3104; 75 ° C) 9
Using a release layer (thickness of 1 μm) formed from 5 parts and 5 parts of an ethylene-vinyl acetate copolymer, setting the thickness of the PET film (base sheet) to 2 μm, The same operation as in Example 1 was performed except that the thickness was 2 μm and the following was used as the carbon black,
A thermal transfer recording medium and an ink ribbon cassette were prepared and printing was attempted. Measure the blackness of the transferred image with a Macbeth densitometer (RD5
As a result, the applied voltage required to obtain a transferred image having a density of 1.2 was 36.5 V. In addition, the running property of the ink ribbon was unstable, especially immediately after the start of printing.・ Carbon black (manufactured by Cabot; MONARCH-1000, particle size: 16 nm, oil absorption: 105 ml / 100 g, specific surface area: 343 m ² / g, coloring power index: 140, apparent density: 175 g / cm ³ )

[0086] As apparent from the results described above, in the thermal transfer recording medium of Examples 1 to 3 the carbon black was allowed specific amount having a particle size and oil absorption of the specific range in the heat-fusible ink layer, sufficient A transfer image having blackness was obtained. Moreover, the running property of the ink ribbon was good. Further, a release layer is provided between the base sheet and the hot-melt ink layer, and 10% of the wax component contained in the release layer is provided.
By making the melt viscosity at 0 ° C. less than 15 cP, the runnability of the ink ribbon was further improved. Further, by setting the drop point of the wax component to 100 ° C. or less,
The runnability of the ink ribbon has been further improved.

On the other hand, in the thermal transfer recording media of Comparative Examples 1 and 2 in which either the particle size or the oil absorption of the carbon black does not satisfy the above ranges, a transfer image having a sufficient blackness cannot be obtained. Furthermore, the running property of the ink ribbon was unstable, especially immediately after the start of printing.

As described above, in the thermal transfer recording medium of the present invention, since the carbon black contained in the heat-fusible ink layer has a specific range of particle diameter and oil absorption, a transfer image with a sufficient degree of blackness can be obtained. It was found that the printing quality was improved. In addition, the running property of the ink ribbon, particularly the running property in low energy printing, was improved.

In the above embodiment, the effect was shown when plain paper was used as the transfer object. However, the transfer object other than plain paper, for example, the preparation of a negative image for printing or the OHP
The same effect as in the above embodiment can be obtained when a transparent sheet used for manufacturing a sheet is used.

[0090]

As described in detail above, according to the present invention, by including a specific amount of carbon black having a specific range of particle diameter and oil absorption in the above-mentioned heat-fusible ink layer, even in low energy printing. A transfer image having a sufficient degree of blackness can be obtained, and a thermal transfer recording medium with improved ink ribbon runnability can be obtained.

By providing the above-mentioned release layer, a thermal transfer recording medium with improved releasability and improved runnability, particularly runnability in low energy printing can be obtained.

Further, by making the thickness of the base sheet, the heat-meltable ink layer and the release layer of the thermal transfer recording medium of the present invention thinner than usual, the number of prints and the amount per one roll of the ink ribbon cassette can be increased. And economic efficiency is improved. In particular, stable running of the ink ribbon can be achieved without using a driving roller.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of an ink ribbon cassette provided with a thermal transfer recording medium of the present invention and having no drive roller, and showing an inner surface of a lower half with an upper half omitted.

FIG. 2 is a plan view showing an embodiment of an ink ribbon cassette provided with a thermal transfer recording medium of the present invention and provided with a driving roller, in which an upper half is omitted and an inner surface of a lower half is viewed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink ribbon cassette 2 Ink ribbon 4 Head part 11 Upper half 12 Lower half 31 Take-up hub 32 Supply hub 51, 52 Drive roller 61, 62, 63, 64 Guide roller 65, 66, 67, 68, 69 Guide roller

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41M 5/38-5/40

Claims (4)

(57) [Claims] 1. A thermal transfer recording medium having a base sheet and at least one heat-fusible ink layer provided on the base sheet, wherein the heat-fusible ink layer has a particle size of 10 to 80 nm. It contains carbon black having an oil absorption of not more than 60 ml / 100 g , and the content of the carbon black is not higher than
A thermal transfer recording medium characterized in that the amount is 40 to 60 parts by weight based on 100 parts by weight of the hydrophilic ink layer . 2. A having a release layer between the substrate sheet and the heat-fusible ink layer, claim 1 thermal transfer recording medium according. 3. The thermal transfer recording medium according to claim 2 , wherein the release layer contains one or more wax components selected from the group consisting of polyethylene wax and paraffin wax. 4. A melt viscosity at 100 ° C. of the release layer is higher than the melt viscosity at 100 ° C. of the heat-fusible ink layer, according to claim 2 or 3 the thermal transfer recording medium according.