JPH0699670A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To provide thermal transfer sheet having the backing layer by which the wear of a thermal head can be reduced and discharge puncture can be prevented from occurring. CONSTITUTION:A recording layer is formed on one side of base film 2, the other side of which is composed of a backing layer 3 containing resin component as binder and anion-based surface active agent having sodium sulfonate group. The backing has the surface resistivity of 10<9>-10<11>OMEGA/cm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet, and more particularly to a thermal transfer sheet which can contribute to improving the durability of a thermal head.

[0002]

2. Description of the Related Art Conventionally, when printing an output print of a computer or a word processor by a thermal transfer method, a thermal transfer sheet having a heat-fusible ink layer on one surface of a base film is used. Further, there is a sublimation thermal transfer system which has excellent continuous gradation and gives a full-color image comparable to a color photograph.

The thermal transfer sheet used in the thermal fusion transfer system or the sublimation thermal transfer system is one in which a recording agent layer made of a heat-fusible ink or a recording agent layer containing a sublimable dye is formed on a substrate film. is there.

Printing and image formation using such a thermal transfer sheet are carried out by stacking a recording material layer and a transfer material and heating them from the back surface of the substrate film with a thermal head.

However, when a heat-sensitive material such as a plastic film is used as the base film, the thermal head adheres (sticks) to the base film during printing, impairing the peeling and slipping property from the thermal head, and The material film is broken. In addition, if the antistatic treatment of the thermal transfer sheet and the transfer target is insufficient,
There is a problem that discharge breakdown occurs in the thermal head due to frictional charging with the thermal head, peeling charging between the thermal transfer sheet and the transfer target, and the like.

Therefore, a back layer is formed on the back surface of the base film. As the back layer, (1)
For example, a resin having high heat resistance, such as a thermosetting resin or a thermoplastic resin having a high softening point, to which silicone or the like is grafted to impart lubricity, (2) a silicone-based or fluorine-based lubricant is added to the resin A material having lubricity, (3) a material containing inorganic particles or crosslinked resin particles having high heat resistance and lubricity to roughen the surface to reduce frictional resistance with a thermal head,
(4) It is proposed to apply or add an antistatic agent or to have an antistatic layer or a metal thin film layer.

[0007]

However, in the back layer of the above (1), although the melting and softening of the substrate film is prevented by the improvement of the heat resistance of the resin used, it is sufficient to suppress the sticking. However, there is a problem that the slipperiness of the resin itself is not obtained, and the addition of the slipperiness to the resin itself lowers the adhesion between the back layer and the substrate film, resulting in the peeling accident of the back layer. In the back surface layer of the above (2), although sticking is prevented, a portion to which heat energy is applied (printed portion, lubricant is bleed out and slipperiness is high) and a portion to which heat energy is not applied ( There is a large difference in slipperiness from the non-printed part), and wrinkles are generated due to printing.
There is also a problem that the dye migrates from the recording agent layer, particularly the recording agent layer containing a sublimable dye, to the back layer and affects the storage stability of the recording agent layer. Further, although the back layer of the above (3) can reduce the coefficient of friction between the thermal transfer sheet and the thermal head,
This may cause white spots on the printed surface and may cause wear of the thermal head, resulting in head residue. In addition, (4) above
Among the back layers of the above, the one coated with a coating type antistatic agent can obtain an antistatic effect, but since the antistatic agent is coated at a high concentration, the surface has a slimy feel and a sticky feeling, and further has a long lasting effect. It had the drawback of being inferior. Further, in the back layer containing the antistatic agent, the proportion of the antistatic agent bleeding to the surface of the back layer is low, it is necessary to increase the addition amount of the antistatic agent to obtain the desired antistatic effect, Therefore, there is a problem that the heat resistance is lowered. Further, a back layer having an antistatic layer or a metal thin film layer can obtain good antistatic effect and heat resistance, but has a problem of high manufacturing cost.

[0008] Further, a surfactant such as a phosphate ester is used as a lubricant having high lubricity, but it may cause thermal decomposition due to heat applied from the thermal head.
There is also a problem that the generated decomposition product deteriorates or corrodes the surface protective film of the thermal head, or attaches as dust.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a thermal transfer sheet having a back layer capable of reducing wear of a thermal head and preventing discharge breakdown. To do.

[0010]

In order to achieve such an object, the present invention provides a base film, a recording agent layer formed on one surface of the base film, and the other of the base films. And a back layer formed on the surface of the back surface, the back layer having a resin component as a binder and an anionic surfactant having a sodium sulfonate group, and having a surface resistivity of 10 ⁹ to 10 ¹¹ Ω / The configuration is such that it is cm ² .

[0011]

[Function] With the resin component as a binder on the back surface layer
Anionic surfactant with sodium sulfonate group
And the surface resistivity of the back layer is 10⁹-10¹¹Ω / cm
²And the anionic surfactant is an antistatic agent.
It also acts as a lubricant at the same time as
Friction between the printer and the thermal head, or thermal transfer
The peeling charge between the sheet and the transferred material is prevented, and
Of the thermal head,
Lip property is improved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of an embodiment of the thermal transfer sheet of the present invention. In FIG. 1, a thermal transfer sheet 1 includes a base film 2, a back layer 3 formed on one surface of the base film 2, and a recording agent layer 4 formed on the other surface of the base film 2. A thermal head (not shown) is in contact with the back surface layer 3.

As the base film 2 used in the present invention,
Various base films used in conventional thermal transfer sheets can be mentioned, and there is no particular limitation. Preferred examples of the base film 2 include polyester, polypropylene, polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), 1,4-polycyclohexylene dimethylene terephthalate (PCT), cellophane, polycarbonate, cellulose acetate, polyethylene, Polyvinyl chloride, polystyrene, nylon, polyimide, polyvinylidene chloride, polyvinyl alcohol, fluororesin, chlorinated rubber, plastic films such as ionomers, condenser paper, papers such as paraffin paper, non-woven fabrics, and the like, and composites thereof. It may be the body.

The thickness of such a base film 2 can be appropriately determined in consideration of the required thermomechanical strength, thermal conductivity, etc., but is generally about 0.5 to 50 μm, preferably 3 μm. It is about 10 μm.

The back surface layer 3 imparts heat resistance, slipping property and antistatic property to the back surface of the base film (the surface in contact with the thermal head), and is a resin component as a binder and an anion type having a sodium sulfonate group. Formed from surfactants and other necessary additives. The surface resistivity of the back surface layer 3 is 10 ⁹ to 10 ¹¹ Ω /
It is cm ² .

The binder resin used for the back layer 3 is, for example, a cellulose resin such as ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, nitrified cotton, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, Examples thereof include polyvinyl acetal, polyvinyl pyrrolidone, acrylic resin, polyacrylamide, vinyl resin such as acrylonitrile-styrene copolymer, polyester resin, polyurethane resin, silicone-modified or fluorine-modified urethane, and the like. Among these, it is preferable to use a binder resin having a reactive group such as a hydroxyl group, and use a polyisocyanate or the like as a crosslinking agent together to form a crosslinked resin layer.

The anionic surfactant having a sodium sulfonate group contained in the back surface layer 3 functions as an antistatic agent and at the same time as a lubricant. Examples of the anionic surfactant include alkyl sulfonate, alkyl benzene sulfonate, alkyl sulfate, sodium alkane sulfonate, and the like, and sodium alkane sulfonate (SAS) -based one represented by the following general formula is particularly preferable.

[0018]

[Chemical 1] In the above general formula, R ₁ and R ₂ represent an alkyl group having 8 to 30 carbon atoms. The anionic surfactant having a sodium sulfonate group as described above is added to the back surface layer 3 in an amount of 5 to 30.
wt%, preferably about 8-15 wt%. When the content of the anionic surfactant is less than 5% by weight, the surface resistivity of the back surface layer becomes higher than 10 ¹¹ Ω / cm ² and frictional electrification between the thermal transfer sheet and the thermal head or the thermal transfer sheet and the transferred material. It is not preferable because peeling charge from the body occurs and discharge destruction of the thermal head occurs. If the content of the anionic surfactant exceeds 30 wt%, the back surface layer 3
There is a slimy feel and a sticky feel on the surface of the recording medium, and the dye migrates from the recording layer 4 to the back surface layer 3, which lowers the storage stability of the recording agent layer 4 and heat resistance, which is not preferable.

Examples of additives that can be used in the back surface layer 3 include lubricants and fillers. As the lubricant, conventionally known ones such as various liquid or solid surfactants and wax-based lubricants can be used.
When the amount of such a lubricant added is large, the heat resistance of the back surface layer 3 is impaired, but in the present invention, as described above, the anionic surfactant having a sodium sulfonate group also acts as a lubricant, so It is possible to reduce the amount of the lubricant added to the back surface layer 3 while imparting the slip property to the back surface layer 3.

The filler has an average particle size of 0.5 to 3
Clay minerals having a layered structure, resin particles, or the like can be used. In particular,
Examples thereof include clay minerals such as kaolin clay, talc, mica and pyrophyllite, and polymethylmethacrylate powder. The content of such a filler in the back surface layer 3 is preferably 3 to 15 wt%. When the average particle size and content of the filler are below the above ranges, blocking occurs during processing, the number of fillers protruding on the surface of the back surface layer 3 decreases, and the contact area with the thermal head increases. Friction resistance will increase. On the other hand, when the average particle diameter and content of the filler exceed the above range, the printed image becomes uneven and white spots occur, the image quality is deteriorated, and the filler dropped from the back surface layer 3 becomes a residue on the thermal head. It is not preferable because it adheres. In the present invention, a primer layer can be provided between the base film 2 and the back surface layer 3. This primer layer is for improving the adhesiveness of the back surface layer 3 to the base film 2, for example, an adhesive resin such as a linear saturated polyester resin having a glass transition temperature of 50 ° C. or higher, or such an adhesive resin. It can be formed by a mixture of the above binder resins.

In the present invention, the recording agent layer 4 may be either a recording agent layer made of hot-melt ink or a recording agent layer containing a sublimable dye. The hot-melt ink used in the present invention is composed of a colorant and a vehicle, and various additives are added if necessary.

The colorant is preferably an organic or inorganic pigment or dye, which has a coloring density required for a recording material and does not deteriorate due to light, heat, temperature or the like. Further, a substance that develops a color by heating or a substance that develops a color when contacted with a substance applied to a transfer target can be used. And the colorant is
In addition to cyan, magenta, yellow, black and the like, colorants of various colors can be used.

The vehicle contains wax as a main component, and in addition, a mixture of wax and a drying oil, a resin, a mineral oil, a derivative of cellulose and rubber, or the like is used. Further, the recording material layer made of the heat-fusible ink may contain a heat-conductive substance in order to provide good heat conductivity and melt transferability. Examples of such heat conductive substances include carbonaceous substances such as carbon black, aluminum, copper, tin oxide, molybdenum disulfide and the like.

Known methods such as hot melt coating, hot lacquer coating, gravure coating, gravure reverse coating, and roll coating can be used to form the recording agent layer on the substrate film using the above heat-meltable ink. Can be mentioned.

The thickness of the recording agent layer 4 made of a heat-fusible ink can be appropriately determined in consideration of the required printing density, thermal sensitivity, etc., and is usually about 0.1 to 30 μm.
A surface layer made of wax may be further formed on the recording agent layer 4. This surface layer forms a part of the transfer film and forms a surface on the side that contacts the transfer target, and seals the printed portion of the transfer target during transfer, prevents scumming, and transfers the heat-meltable ink. It acts to improve the adhesion to the body. The wax used for forming the surface layer is the same as the wax used for the recording agent layer.

On the other hand, the dye used for forming the recording agent layer containing a sublimable dye may be a conventionally known sublimable dye used in a thermal transfer sheet. Specific examples of sublimable dyes include MS Red G and Macrolex R as red dyes.
ed Violet R, Ceres Red 7B, Samaron Red HBSL, Reso
lin Red F3BS, etc., yellow dyes such as Holon Brilliant Yellow 6GL, PTY-52, Macrolex Yellow 6G, etc., and blue dye, Kayaset Blue 71.
4, Waxolin Blue AP-FW, Holon Brilliant Blue SR, MS Blue 100 and the like.

As the binder resin for supporting the above sublimable dye, any conventionally known binder resin can be used, for example, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, nitrified cotton, etc. The cellulose resins, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, polyacrylamide, and other vinyl resins, polyester resins, and the like. Among these binder resins, cellulose type, acetal type, butyral type and polyester type are particularly preferable.

The recording agent layer 4 containing a sublimable dye is formed, for example, by adding the above-mentioned sublimable dye, binder resin and other necessary additives to a suitable solvent and dissolving or dispersing each component to form an ink. Is prepared, and this ink is applied onto a substrate film and dried, which can be performed. The thickness of the recording agent layer 4 is preferably about 0.2 to 5 μm, and the amount of the sublimable dye contained in the recording agent layer 4 is preferably about 5 to 90% by weight.

Next, the present invention will be described in more detail with reference to experimental examples. (Experimental example) First, seven kinds of back layer inks I-1 to I-7 having the composition shown in Table 1 and composed of the following constituent materials were prepared.

Ink for back layer I • Polyvinyl butyral resin (S-LEX BX-1 manufactured by Sekisui Chemical Co., Ltd.) A part by weight Polyisocyanate (Bernock D-750 manufactured by Dainippon Ink and Chemicals, Inc.) B part by weight・ Anionic surfactant (SAS type) (Atrai AS-1000 manufactured by Nikko Petrochemical Co., Ltd.) C weight part ・ Kaolin clay (average particle size = 3 μm or less) (Infilm 813 manufactured by ECC JAPAN Co., Ltd.) D Parts by weight-lubricant (NONION OP-85R manufactured by NOF CORPORATION) ... E parts by weight-methyl ethyl ketone / toluene (mixing ratio 1: 1) ... F parts by weight

[0031]

[Table 1] Further, the following six kinds of back layer inks II to VII were prepared in which the anionic surfactant, the filler and the lubricant were replaced.

Ink for back layer II-Polyvinyl butyral resin (Sekisui Chemical Co., Ltd. S-REC BX-1) 43 parts by weight-Polyisocyanate (Dainippon Ink and Chemicals Co., Ltd. Barnock D-750) 57 parts by weight・ Anionic surfactant (SAS type) (Kyoeisha Yushi-Kogaku Kogyo Co., Ltd. Destat P-540)… 8 parts by weight ・ Talc (average particle size = 1.8 μm) (Nippon Talc Co., Ltd. Microace L- 1) 6 parts by weight-Lubricant (TS-30 manufactured by Nikko Chemicals Co., Ltd.) 15 parts by weight-Methyl ethyl ketone / toluene (mixing ratio 1: 1) 900 parts by weight Ink for back layer III-Polyvinyl butyral resin (Sekisui Chemical Co., Ltd.) S-REC BX-1 manufactured by Co., Ltd. 43 parts by weight Polyisocyanate (Bernock D-750 manufactured by Dainippon Ink and Chemicals, Inc.) 57 parts by weight Anion-based interface Sexual agent (SAS type) (Chemist 3033 manufactured by Sanyo Kasei Co., Ltd.) 15 parts by weight-Kaolin clay (average particle size = 0.6 μm) (ASP-600 manufactured by Tsuchiya Kaolin Co., Ltd.) 15 parts by weight-Lubricant ( Nippon Oil & Fat Co., Ltd. Unistar H381R) 10 parts by weight Methyl ethyl ketone / toluene (mixing ratio 1: 1) 900 parts by weight Back layer ink IV Polyvinyl butyral resin (Sekisui Chemical Co., Ltd. S-REC BX-1) 29.5 parts by weight ・ Polyisocyanate (Bernock D-750 manufactured by Dainippon Ink and Chemicals, Inc.) ... 70.5 parts by weight ・ Anionic surfactant (SAS system) (Atrai AS- manufactured by Nikko Petrochemical Co., Ltd.) 4000) 5 parts by weight-talc (average particle size = 2.2 μm) (manufactured by Nippon Talc Co., Ltd., Microace LG) ... 10 parts by weight-lubricant (Daiichi Kogyo Seiyaku Co., Ltd., PRYSURF A208S) ... 23 parts by weight-Methyl ethyl ketone / toluene (mixing ratio 1: 1) ... 600 parts by weight Ink for back layer V-Polyvinyl butyral resin (Eslec BX-1 manufactured by Sekisui Chemical Co., Ltd.) 43 parts by weight-Polyisocyanate (Dainippon Ink) Chemical Industry Co., Ltd. Bernock D-750) ... 57 parts by weight Anionic surfactant (Lion Co., Rheostat P-200) ... 10 parts by weight Kaolin clay (average particle size = 3 μm or less) (ECC JAPAN Infilm 813 manufactured by Incorporated Co., Ltd. 6 parts by weight Lubricant (Nonion OP-85R manufactured by NOF CORPORATION) 30 parts by weight Methyl ethyl ketone / toluene (mixing ratio 1: 1) 900 parts by weight Back layer ink VI Polyvinyl butyral resin (Sekisui Chemical Co., Ltd. S-REC BX-1) 43 parts by weight Polyisocyanate (Dainippon Ink and Chemicals Co., Ltd. Verno KU D-750) 57 parts by weight Anionic surfactant (SAS) (Nippon Petrochemical Co., Ltd. Atrai AS-4000) 20 parts by weight Kaolin clay (average particle size = 0.3 μm) (Tsuchiya) Kaolin Co., Ltd. ASP-072) 15 parts by weight Lubricant (Nippon Yushi Co., Ltd. Unistar H381R) 20 parts by weight Methyl ethyl ketone / toluene (mixing ratio 1: 1) 900 parts by weight Back layer ink VII Polyvinyl butyral resin (S-Lex BX-1 manufactured by Sekisui Chemical Co., Ltd.) 43 parts by weight Polyisocyanate (Bernock D-750 manufactured by Dainippon Ink and Chemicals, Inc.) 57 parts by weight Anionic surfactant (SAS-based) ) (Nichiko Petrochemical Co., Ltd. Atrai AS-4000) 18 parts by weight Polymethylmethacrylate powder (average particle size = 5 μm) (Soken Chemical Co., Ltd. MR-7G)… 5 parts by weight Lubricant Nippon Oil & Fats Co., Ltd. Unistar H381R) 25 parts by weight Methyl ethyl ketone / toluene (mixing ratio 1: 1) 900 parts by weight Furthermore, back layer inks VIII and IX having the following composition containing no anionic surfactant were prepared. did.

Back Layer Ink VIII (Comparison) -Polyvinyl butyral resin (Sekisui Chemical Co., Ltd. S-REC BX-1) ... 29.5 parts by weight-Polyisocyanate (Dainippon Ink and Chemicals Co., Ltd. Burnock D-750) ) ... 70.5 parts by weight-talc (average particle size = 1.8 μm) (manufactured by Nippon Talc Co., Ltd. Microace L-1) ... 8 parts by weight-Lubricant (Daiichi Kogyo Seiyaku Co., Ltd. PRYSURF A208S) 20 parts by weight Methylethylketone / toluene (mixing ratio 1: 1) 600 parts by weight Ink for back layer IX (comparison) Polyvinyl butyral resin (Eslec BX-1 manufactured by Sekisui Chemical Co., Ltd.) 89.5 parts by weight Polyisocyanate (Bernock D-750 manufactured by Dainippon Ink and Chemicals, Inc.) ... 70.5 parts by weight Polymethylmethacrylate powder (average particle size = 5 μm) (MR manufactured by Soken Chemical Co., Ltd.) -7G) ... 10 parts by weight-Lubricant (Prysurf A208S manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) ... 25 parts by weight-Methyl ethyl ketone / toluene (mixing ratio 1: 1) ... 600 parts by weight In addition, a recording agent layer having the following composition An ink for use was prepared.

Ink No. 1 for recording material layer: Paraffin wax: 10 parts by weight Carnauba wax: 10 parts by weight Ethylene / vinyl acetate copolymer (Sumitate HC-10 Sumitate HC-10): 1 part by weight・ Carbon black (Shikai 3 manufactured by Tokai Electrode Co., Ltd.) 2 parts by weight Ink No. 2 for recording material layer ・ Disperse dye (Kayaset Blue 714 manufactured by Nippon Kayaku Co., Ltd.) 4 parts by weight ・ Polyvinyl butyral resin (Sekisui Chemical Co., Ltd. S-REC BX-1) 4.3 parts by weight Methyl ethyl ketone / toluene (mixing ratio 1: 1) 80 parts by weight Isobutanol 10 parts by weight Next, the above-mentioned back layer ink and recording. 4.5 μm thick polyethylene terephthalate (P
ET) film (Lumirror manufactured by Toray Industries, Inc.) is provided with a back layer on one side and a recording agent layer on the other side, and 30 kinds of thermal transfer sheets (Sample 1 to Sample 30) shown in Table 2 are prepared. Created.

In this case, the back layer was formed by coating the back layer ink with a wire bar coater (coating amount 1.0 g / m ² ) and drying with warm air. The recording agent layer made of heat-meltable ink was applied to the recording agent layer ink No. 1 by a roll coating method using hot melt at 130 ° C. (coating amount 4.0 g /
m ² ) and formed. The recording agent layer containing a sublimable dye was formed by coating the recording agent layer ink No. 2 with a wire bar coater (coating amount 1.0 g / m ² ) and drying with warm air.

Next, with respect to each of the thermal transfer sheets prepared as described above, the surface resistivity of the back surface layer was measured, and printing was carried out under the following conditions to discharge the thermal head, remove dust, sticking, and wrinkle. The state, the storability of the recording agent layer, the print quality, and the occurrence of blocking between the back layer and the PET film were evaluated. The evaluation results are shown in Tables 2 and 3.

(Printing conditions for samples 1 to 15) Line cycle: 12 msec. Pulse width: 3 msec. Platen pressure: 4 kg Printing distance: 3 km (Printing conditions for samples 16 to 30) Line cycle: 16 msec. Pulse width: 8 msec. Platen pressure: 4kg Printing distance: 3km (Evaluation method) (1) Surface resistivity Using Hiresta IP manufactured by Mitsubishi Yuka, 25 ° C, 45% R
Measure the surface resistivity when applying 500 V under H condition.

(2) Discharge destruction of thermal head and adhesion of head dregs The thermal head after printing under the above conditions is observed with a microscope. (3) Sticking and wrinkling After printing under the above conditions, it is judged visually.

(4) Storability (dye transferability) The surface of the recording material layer containing the sublimable dye and the back layer are combined,
A load of 200 g / cm ² was applied, and the mixture was left at 60 ° C. for 1 day and evaluated for dye transfer to the back surface layer.

(5) Blocking A PET film was put on the back layer and left at 60 ° C. under a load of 200 g / cm ² for 1 day to evaluate the degree of adhesion of the back layer to the PET film.

(6) Print quality After printing under the above conditions, the state of occurrence of print unevenness and white spots is observed.

[0042]

[Table 2]

[0043]

[Table 3] As shown in Table 2 and Table 3, the back surface layer contains an anionic surfactant having a sodium sulfonate group,
Thermal transfer sheets (samples 1-3, 6-13, sample 16-) having a surface resistivity of the back layer in the range of 10 ⁹ -10 ¹¹ Ω / cm ^2.
18, 21-28), printing had almost no adverse effect on the thermal head. Particularly, when the content of the anionic surfactant in the back layer is 5 to 30% by weight (Samples 1 to 3, 7 to 13, Samples 16 to 18, 22)
28), a remarkable effect was seen. Further, when polyisocyanate was used as the curing agent, a sufficient antistatic effect was observed by using the SAS-based anionic surfactant (comparison between sample 1 and sample 10, comparison between sample 16 and sample 25). ). Furthermore, the anionic surfactant having a sodium sulfonate group does not act as a lubricant,
It was also confirmed that the amount of lubricant added could be reduced (comparison between sample 1 and sample 7, comparison between sample 16 and sample 22).

The thermal transfer sheets (samples 13, 15 (comparative), 28, 30 (samples 13, 15 (comparative), 28, 30 ( In (Comparison)), dust adhesion to the thermal head was observed. On the other hand, blocking occurred in the thermal transfer sheet (Samples 12 and 27) including the back layer formed of the back layer ink VI using the filler having the average particle size of less than 0.5 μm. From this, it was confirmed that the average particle diameter of the filler is preferably in the range of 0.5 to 3 μm.

[0045]

As described in detail above, according to the present invention, frictional electrification between the thermal transfer sheet and the thermal head or peeling electrification between the thermal transfer sheet and the transfer target is prevented, and
Sticking is prevented, peeling from the thermal head and slip properties are improved, and images with good print quality can be formed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an example of a thermal transfer sheet of the present invention.

[Explanation of symbols]

 1 ... Thermal transfer sheet 2 ... Base film 3 ... Back surface layer 4 ... Recording agent layer

Claims (6)

[Claims] 1. A substrate film, a recording agent layer formed on one surface of the substrate film, and a back layer formed on the other surface of the substrate film, wherein the back layer is A thermal transfer sheet comprising a resin component as a binder and an anionic surfactant having a sodium sulfonate group, and having a surface resistivity of 10 ⁹ to 10 ¹¹ Ω / cm ² . 2. The thermal transfer sheet according to claim 1, wherein the back layer contains a curing agent. 3. The thermal transfer sheet according to claim 2, wherein the curing agent is polyisocyanate. 4. The backside layer contains a filler in an amount of 3 to 15% by weight, and the filler has a layered structure and an average particle size of 0.5 to 0.5.
The thermal transfer sheet according to claim 1, wherein the thermal transfer sheet is a clay mineral having a thickness of 3 μm. 5. The thermal transfer sheet according to claim 1, wherein the back surface layer contains the anionic surfactant in an amount of 5 to 30% by weight. 6. The anionic surfactant is sodium alkane sulfonate.
6. The thermal transfer sheet according to any one of 5 to 6.