JP2926766B2 - Thermal transfer recording medium - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording medium. More specifically, the present invention relates to a thermal transfer recording medium. The present invention relates to a heat-sensitive transfer recording medium capable of forming a high-quality printed image free from background smear with high resolution on transfer paper having high smoothness and having high confidentiality.

[Related Art and Problems to be Solved by the Invention] In recent years, by adopting a thermal transfer recording method for a facsimile, storage stability of a recorded image is improved as compared with a thermal coloring method used for a conventional facsimile. At the same time, attempts have been made to enable printing on plain paper.

However, when a conventional thermal transfer recording medium is used in combination with a facsimile line printer, a line head generally used in a line printer is
Insufficient pressing force compared to serial heads, resulting in insufficient heat conduction, so that high quality printed images can be formed even if the surface of the transfer paper used is high. There is a problem that it is difficult.

Further, when a conventional thermal transfer recording medium is used in a high-temperature environment such as a facsimile apparatus where power is easily turned on and heat is easily stored all day, for example, as shown in FIG. In addition, the ink layer B containing the heat-fusible substance is separated inside the ink layer B as shown by the broken line in FIG. However, there is a problem that the film thickness becomes thin and the print density decreases.

Further, in the conventional thermal transfer recording medium, after the ink layer is transferred to the transfer receiving paper, a so-called white spot corresponding to the shape of the printed image is formed, which is readable. is there.

Further, in general, in order to improve the quality of a printed image formed by a thermal transfer recording medium and obtain a clear printed image, it is desired that the resolution be high and the background smear be hardly generated.

 The present invention has been made based on the above circumstances.

SUMMARY OF THE INVENTION An object of the present invention is to form a high-quality printed image with high resolving power and no background smear on a transfer paper having a high surface smoothness without a decrease in density even in a high-temperature environment, and to maintain confidentiality. Another object of the present invention is to provide a heat-sensitive transfer recording medium having high heat resistance.

[Means for Solving the Problems] In order to solve the above problems, as a result of intensive studies by the present inventors, a specific non-transfer layer containing a thermoplastic resin at a specific ratio is provided on a support. Styrene resin and / or styrene having a weight average molecular weight in a specific range.
In a heat-sensitive transfer recording medium provided with a specific transfer layer containing a (meth) acrylate copolymer resin, surprisingly, even in a high-temperature environment, there is no decrease in density, and particularly high surface smoothness. The present invention has been found that a high-quality printed image free from background smear can be formed on a transfer receiving paper with high resolution and high secrecy is maintained.

The constitution of the present invention comprises, on one surface of the support, a non-transfer layer containing a thermoplastic resin and a coloring material, and a styrene having a weight average molecular weight in the range of 100 to 30,000 together with the heat-fusible substance and the coloring material. A transfer layer containing a resin and / or a styrene- (meth) acrylate copolymer resin is laminated in this order, and at least 80% by weight of the binder component in the non-transfer layer is the thermoplastic resin. This is a thermal transfer recording medium characterized by the following.

Hereinafter, the thermal transfer recording medium of the present invention will be described in detail for a support, a non-transfer layer, a transfer layer, and the like.

—Support— The support in the thermal transfer recording medium of the present invention preferably has good heat resistance and high dimensional stability.

Examples of the material include papers such as plain paper, condenser paper, laminated paper, and coated paper; resin films such as polyethylene, polyethylene terephthalate, polystyrene, polypropylene, and polyimide; composites of paper and resin film; and aluminum foil. Any of these metal sheets is suitably used.

The thickness of the support is usually 30 μm or less, preferably 2 to
It is in the range of 6 μm. When the thickness of the support exceeds 30 μm, the thermal conductivity is deteriorated, and the print quality may be deteriorated.

In the thermal transfer recording medium of the present invention, the configuration on the back side of the support is arbitrary, and for example, a backing layer such as an anti-sticking layer may be provided.

—Non-Transfer Layer— One of the important points in the present invention is that between the support and the transfer layer described in detail below, at least 80% by weight of the binder component is a thermoplastic resin and The purpose of the present invention is to provide a non-transfer layer.

By providing the non-transfer layer, in the thermal transfer recording medium of the present invention, when the transfer layer to be described in detail below is separated from the support side, the transfer layer is surely separated at the interface of the non-transfer layer even in a high temperature environment. As a result, it is possible to form a clear print image with high density.

Further, since the non-transfer layer remains on the support even after the transfer layer is transferred to the medium to be transferred and contains a coloring material, the occurrence of the so-called white spots described above is prevented, and The confidentiality of the thermal transfer recording medium is improved.

Such actions or functions of the non-transfer layer are mainly
This is provided by the thermoplastic resin and the coloring material contained in the non-transfer layer.

Examples of the thermoplastic resin in the non-transfer layer include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, acrylic resins, vinyl chloride resins, cellulose resins, epoxy resins, rosin resins, and vinyl acetate. Resin, cellulose resin, ionomer resin, polyacetal, polycarbonate,
Examples thereof include polyphenylene oxide and noryl resin, polysulfone, fluororesin, and silicone resin.

Among these, preferred are polyester resins,
Polyurethane resin, epoxy resin and vinyl chloride resin.

The thermoplastic resin may be used singly, or 2
A combination of more than one species may be used.

In any case, in the present invention, it is necessary that 80% by weight or more of the binder component in the non-transfer layer is the thermoplastic resin.

The non-transfer layer contains the coloring material together with the thermoplastic resin.

The coloring material has an effect of preventing the so-called self-extracting portion from being generated after the transfer layer is transferred to the transfer medium.

Therefore, the color of the color material contained in the non-transfer layer is preferably the same as the color of the color material in the transfer layer described in detail below.

As the color material, those similar to the color materials in the transfer layer described in detail below can be suitably used.

The content of the coloring material in the non-transfer layer is usually 60% by weight or less, preferably 10 to 50% by weight.

The non-transfer layer may contain a heat-fusible substance together with the thermoplastic resin and the coloring material.

As the heat-fusible substance, the same heat-fusible substance that can be contained in the transfer layer described in detail below can be suitably used.

When the non-transfer layer contains the heat-fusible substance, the content of the heat-fusible substance is usually 50% by weight or less, preferably 30% by weight or less.

The non-transfer layer containing the above components can be coated on the support by a coating method such as an aqueous coating method, a coating method using an organic solvent, or a hot melt coating method.

The thickness of the non-transfer layer is usually in the range of 0.3 to 3 μm, preferably in the range of 0.2 to 2 μm. By setting this layer thickness within the above range, the object of the present invention can be sufficiently achieved.

On this non-transfer layer, a transfer layer described below is laminated adjacent thereto.

-Transfer layer- The transfer layer is composed of a heat-fusible substance, a coloring material, and a weight average molecular weight of 1,
A styrene resin and / or a styrene- (meth) acrylate copolymer resin in the range of 000 to 30,000.

Examples of the heat-fusible substance include carnauba wax,
Vegetable waxes such as wood wax, ouriculi wax and Spar wax; animal waxes such as beeswax, insect wax, shellac wax and whale wax; petroleum waxes such as paraffin wax, microcrystal wax, polyethylene wax, ester wax and acid wax; And waxes such as mineral waxes such as montan wax, ozokerite and ceresin. In addition to these waxes, higher fatty acids such as palmitic acid, stearic acid, margaric acid and behenic acid; palmityl alcohol, stearyl Higher alcohols such as alcohol, behenyl alcohol, marganyl alcohol, myricyl alcohol and eicosanol; cetyl palmitate, myricyl palmitate, cetyl stearate and myricyl stearate. Grade fatty esters; acetamide,
Examples include amides such as propionamide, palmitamide, stearamide and amide wax; and higher amines such as stearylamine, behenylamine and palmitylamine.

These may be used alone or in combination of two or more.

Among these, preferred are waxes having a melting point in the range of 50 to 120 ° C. measured using Yanagimoto MJP-2.

The content of the heat-fusible substance in the transfer layer is usually
Preferably it is in the range of 30 to 90% by weight.

Examples of the coloring material include pigments such as inorganic pigments and organic pigments, and dyes.

Examples of the inorganic pigment include titanium dioxide, carbon black, zinc oxide, Prussian blue, cadmium sulfide, iron oxide, and chromates of lead, zinc, barium, and calcium.

Examples of the organic pigment include azo-based, thioindigo-based, anthraquinone-based, anthranthrone-based, and triphenedioxazine-based pigments, vat dye pigments, phthalocyanine pigments such as copper phthalocyanine and its derivatives, and quinacridone pigments.

Examples of the organic dye include an acid dye, a direct dye, a disperse dye, an oil-soluble dye, and a metal-alloy oil-soluble dye.

Among these various coloring materials, carbon black is particularly preferred.

The content of the coloring material in the transfer layer is usually in the range of 5 to 30% by weight, preferably in the range of 10 to 25% by weight.

One of the important points in the present invention is that the transfer layer, together with the heat-fusible substance and the colorant, has a weight-average molecular weight ( _Mw ) of 100 to 30,000 in both styrene resin and / or styrene- ( (Meth) acrylate copolymer resin. The fact that the transfer layer contains this specific resin is important in order to form a high-quality printed image without a decrease in density even in a high-temperature environment.

That is, since the transfer layer contains the specific styrene resin and / or styrene- (meth) acrylate copolymer resin, the releasability of the transfer layer at the interface with the non-transfer layer and the transfer medium The fixability of the transfer layer is improved.

However, in order for such an expected effect to be sufficiently exhibited, the styrene resin or the styrene- (meth)
The weight average molecular weight ( _Mw ) of the acrylate copolymer resin is in the range of 100 to 30,000, preferably 300 to 10,000.
Must be in the range of

In addition, the styrene resin or the styrene- (meth) acrylate copolymer resin has a softening point of 50 to 140 ° C, preferably 60 to 120 ° C, measured using a falling flow tester. If the softening point is outside the above range, the transfer layer may have insufficient fixability to the medium to be transferred, or the transfer layer may not peel off at the interface with the non-transfer layer.

The content of the styrene resin and / or (meth) acrylate copolymer resin in the transfer layer is usually
In the range of 1 to 60% by weight, preferably 2 to 50% by weight
Within the range.

The transfer layer preferably further contains a tackifier together with the hot-melt substance, the coloring material, the styrene resin and / or the (meth) acrylate copolymer resin. When the tackifier is contained, the adhesiveness of the transfer layer to the medium to be transferred is improved.

The tackifier used in the present invention is a hydrocarbon compound having a polar group such as a hydroxyl group and a carboxyl group, and a substance which exhibits adhesive strength when used alone or in combination with other components. It is.

Examples of such tackifiers include unmodified or modified rosin tackifiers, water-added rosin-based tackifiers, rosin maleic acid-based tackifiers, polymerized rosin-based tackifiers, and rosin-phenol-based tackifiers. Rosin-based tackifiers, terpene-based tackifiers, petroleum resin-based tackifiers, and modified tackifiers thereof can be mentioned.

When the tackifier is used, the content of the tackifier in the transfer layer is usually 1 to 60% by weight, preferably 2 to 50% by weight.

Further, the transfer layer may contain a surfactant such as a polyoxyethylene chain-containing compound in addition to the above-mentioned components.

The transfer layer further comprises inorganic or organic fine particles (metal powder,
(Eg, silica gel) and oils (eg, linseed oil, mineral oil, etc.).

The transfer layer can be coated on the non-transfer layer by using a coating method such as an aqueous coating method or a coating method using an organic solvent.

The thickness of the transfer layer is usually in the range of 1 to 10 μm, preferably in the range of 2 to 6 μm.

-Others- The thermal transfer recording medium of the present invention usually has the non-transfer layer and the transfer layer applied in this order on the support,
If desired, it can be manufactured by cutting into a desired shape through a drying step, a surface smoothing step, and the like.

The thermal transfer recording medium thus obtained can be used in the form of a wide tape or a typewriter ribbon generally used for a line printer or the like, but the planar shape of the thermal transfer recording medium of the present invention can be used. Preferred is a sheet having substantially the same width as the recording paper used in the line printer.

The thermal transfer method using the thermal transfer recording medium of the present invention,
Although not different from the normal thermal transfer recording method, a case where a most typical thermal head is used as a heat source will be described as an example.

First, the transfer layer of the thermal transfer recording medium and the medium to be transferred, such as plain paper, are brought into close contact with each other, and a heat pulse is applied by a thermal head to locally heat the heat-softening color material layer corresponding to a desired printing or transfer pattern. I do.

The temperature of the heated portion of the transfer layer rises, and for example, as shown in FIG. 1 (a), the transfer layer 1 quickly softens and peels off from the interface with the non-transfer layer 2 to transfer the transfer medium. Transcribed above. After the transfer layer 1 has been transferred, the non-transfer layer 2 remains on the support 3 as shown in FIG.

[Examples] Next, examples of the present invention and comparative examples are shown, and the present invention will be described more specifically.

(Example 1) Solvent coating using a wire bar on a 4.5 μm-thick polyethylene terephthalate film with the following non-transfer layer composition so as to have a layer thickness of 10 μm over a length corresponding to the width of JIS A4 paper. The non-transferable layer was formed on the thermal transfer recording medium of the present invention by a coating method.

Non-transfer layer composition Polyester resin ... 80% by weight ["Byron 200" manufactured by Toyobo Co., Ltd.] Carbon black ... 20% by weight Next, the following transfer layer composition The material was applied on the non-transfer layer by a hot melt coating method using a gravure roll so as to have a layer thickness of 4 μm to form a transfer layer, thereby obtaining a thermal transfer recording medium of the present invention.

Transfer layer assembly organism Styrene resin ・ ・ ・ ・ ・ ・ ・ ・ ・ 10% by weight (weight average molecular weight M _w = 1,000) Paraffin wax ・ ・ ・ ・ ・ ・ 70% by weight Carbon black ・ ・ ・ ・ ・ ・ ・ 20 Wt% The obtained thermal transfer recording medium is transferred to a thermal printer (26
0mm width line head, 180 DPI, platen rubber hardness 40 degrees)
Was used for recording (printing) on highly smooth paper (Beck smoothness: 100 seconds), and the reduction in the density of the printed image, the resolving power, background contamination, and confidentiality were evaluated.

 The results are shown in Table 1.

The density reduction, resolution, background smear, and confidentiality of the printed image were evaluated as follows.

Density reduction: Printing was performed under the conditions of a temperature of 40 ° C. in the printer, and the reflection density of the printing was evaluated in the following two grades.

 ：: Print reflection density 1.4 or more.

 X: Print reflection density less than 1.4.

Resolution: The reproducibility of a 1-dot ruled line was visually evaluated in the following two stages.

 ：: No break.

 ×: There is a break.

Background dirt: The dirt at the head of printing was visually observed and evaluated in the following two stages.

 ：: No stain on the top of printing.

 X: Staining occurred at the top of printing.

Confidentiality: Visual observations were made of reflected marks after reflection with the reflected light.

 ：: No loss after printing.

 Δ: There is some dropout.

(Example 2) Example 1 was carried out in the same manner as in Example 1 except that the following transfer layer composition was used instead of the transfer layer composition used in Example 1.

 The results are shown in Table 1.

Transfer layer assembly styrene-acrylic acid ester copolymer resin ······ 15% by weight (weight average molecular weight M _w = 5,000) Paraffin wax ···· 65% by weight carbon black ··· ... 20% by weight (Comparative Example 1) Same as Example 1 except that the following transfer layer composition was used instead of the transfer layer composition used in Example 1 in Example 1 Then, a non-transfer layer and a transfer layer were laminated on the support in this order to produce a thermal transfer recording medium, and the thermal transfer recording medium was evaluated.

 The results are shown in Table 1.

Transfer layering composition Ethylene-vinyl acetate copolymer ... 10% by weight (vinyl acetate content 28% by weight) Paraffin wax ... 70% by weight Carbon black ... 20% by weight (Comparative Example 2) On the support in the same manner as in Example 1 except that the following transfer layer composition was used instead of the transfer layer composition used in Example 1 above. Then, a thermal transfer recording medium having a non-transfer layer and a transfer layer laminated in this order was manufactured, and the thermal transfer recording medium was evaluated.

 The results are shown in Table 1.

Transfer layer assemblage Paraffin wax ... 80% by weight Carbon black ... 20% by weight (Comparative Example 3) Transfer layer composition used in Example 1 in Example 1 In the same manner as in Example 1 except that the following transfer layer composition was used instead of the transfer material, a heat-sensitive transfer recording medium having a specific transfer layer and a transfer layer laminated on the support in this order was manufactured. Then, the thermal transfer recording medium was used in Example 1 described above.
An evaluation of confidentiality similar to that described above was performed.

Transfer layer composition Polyester resin 55% by weight Paraffin wax 25% by weight Carbon black 20% by weight As a result of the evaluation, the confidentiality was Δ △ ×.

Comparative Example 4 The same transfer layer composition as in Example 1 was used except that a styrene resin having a weight average molecular weight of 360,000 was used. A thermal transfer recording medium was manufactured in the same manner, and the same thermal evaluation as in Example 1 was performed on the thermal transfer recording medium.

 As a result of the evaluation, the resolving power was x.

(Evaluation) As is evident from Table 1, the thermal transfer recording medium of the present invention has no decrease in density even in a high temperature environment,
It has been confirmed that a high-resolution printed image having high resolving power, no background contamination, and excellent secrecy can be formed.

[Effects of the Invention] According to the present invention, (1) the non-transfer layer laminated on the support comprises a thermoplastic resin at 80% by weight or more of the binder component, and the transfer layer laminated on the non-transfer layer is Since it contains a styrene resin and / or a styrene- (meth) acrylate copolymer resin having a weight average molecular weight in a specific range, the transfer layer is always a non-transfer layer even in a high temperature environment such as a line printer of a facsimile machine. It is possible to form a high-quality printed image with no decrease in density and no stickiness of the transfer layer and no generation of background stain, because the transfer layer is stable. After being transferred onto the transfer-receiving medium, the non-transfer layer remaining on the support contains the coloring material, so that a readable so-called white spot does not occur, and the confidentiality is high, 3) Moreover, it is possible to provide a high-performance thermal transfer recording medium having resolution is high, a variety of advantages such.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are cross-sectional views showing the relationship between a transfer layer and a non-transfer layer in a thermal transfer recording medium of the present invention, and FIG. 2 is an example of a conventional thermal transfer recording medium. FIG. 1 ... transfer layer, 2 ... non-transfer layer, 3 ... support

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshihisa Takeyama 1 Sakuramachi, Hino-shi, Tokyo Konica Corporation (72) Inventor Takao Abe 1 Sakuramachi, Hino-shi, Tokyo Konica Corporation (56) References JP-A-1-93393 (JP, A) JP-A-1-157889 (JP, A) JP-A-65-11981 (JP, A) JP-A-63-1593 (JP, A) JP-A-61 −244591 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41M 5/38-5/40

Claims (1)

(57) [Claims] 1. A non-transfer layer containing a thermoplastic resin and a coloring material on one surface of a support, and a styrene resin having a weight-average molecular weight in the range of 100 to 30,000 together with a heat-fusible substance and a coloring material. And / or a transfer layer containing a styrene- (meth) acrylate copolymer resin is laminated in this order, and at least 80% by weight of the binder component in the non-transfer layer is the thermoplastic resin. A thermal transfer recording medium characterized by the following.