JP2510723B2 - Thermal transfer recording method - Google Patents

Description

The present invention relates to a heat-sensitive transfer recording method capable of obtaining excellent recording even if the amount of the heat-sensitive transfer material used is reduced.

[Conventional technology]

In addition to the general features of the thermal recording method that the device used is lightweight and compact, there is no noise, excellent operability and storability, the thermal transfer recording method does not require coloring type processed paper, and the recorded image It has excellent durability and has been widely used recently.

This recording method is generally performed on a sheet-shaped support,
A heat-sensitive transfer material obtained by coating a heat-transferable ink layer in which a coloring material is dispersed in a heat-meltable binder is used, and the heat-sensitive transfer material is superposed so that the heat-transferable ink layer contacts the recording medium, Heat is supplied from the base material side by a heat head to transfer the melted ink layer to a recording medium, thereby forming a transferred and recorded image on the recording medium according to a heat supply shape (pattern).

[Problems to be Solved by the Invention]

In the conventional thermal transfer recording, since the thermal transfer ink is almost completely transferred from the thermal transfer material to the recording medium by applying heat once, the thermal transfer ink is disposable, the running cost is high, and the used thermal transfer material is used. There was also a concern that the secret would leak out.

On the other hand, JP-A-57-83471 and JP-A-58-201
A recording method for reducing the usage amount of the heat-sensitive transfer material by providing a relative speed between the heat-sensitive transfer material and the recording medium, as in Japanese Patent No. 686 or Japanese Patent Publication No. 62-58917 (hereinafter referred to as double-density recording). ) Is proposed. However, this recording method has conventionally had the following problems.

In double-density recording, as will be described later in detail, a portion where the heat transferable ink layer of the heat-sensitive transfer material is heated once,
There is a part where heating is performed a plurality of times. For this reason, the temperature reached by the heat transferable ink layer varies greatly depending on the location, the density uniformity of the recorded image is significantly deteriorated, and there is a problem that the cover ledge on the surface of the recording medium becomes insufficient. (If the recording medium is paper, many voids were generated).

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thermal transfer recording method capable of obtaining a recorded image with uniform density by double-density recording and excellent cover coverage on the surface of a recording medium. .

[Means for solving the problem]

The thermal transfer recording method of the present invention uses a thermal transfer material having a thermal transferable ink layer having a melt viscosity satisfying the following formula (1) on a support, and a recording medium moves to a recording head within the same time. It is characterized in that the distance that the thermal transfer material moves with respect to the recording head is shorter than the distance.

However, η _{100 ℃} is melt viscosity at 100 ℃ (cps) η _{150 ℃} is melt viscosity at 150 ℃ (cps) Hereinafter, the present invention will be described with reference to the drawings.

In the following description, “%” and “part” representing the quantitative ratio are by weight unless otherwise specified.

The thermal transfer recording method of the present invention, as shown in FIG.
The thermal transfer material 1 and the recording medium 2 such as paper are overlapped to form the thermal head 3.
By heating at 1, the thermal transfer ink of the thermal transfer material 1 is transferred to the recording medium 2 to obtain a recorded image.
The thermal transfer material 1 and the recording medium 2 are the capstan rotor 12
By the rotation of the pinch roller 13 and the platen roller 11, the pinch roller 13 and the platen roller 11 continuously move in the directions of arrows A and B, respectively, and recording is performed on the recording medium 2 one after another. Capstan roller 12
The pinch roller 13 is driven by a motor 14, and the platen roller 12 is driven by a motor 15. The conveyed heat-sensitive transfer material 1 is wound by a winding roller 10 driven by a motor 14. Reference numeral 16 denotes a spring, which presses the thermal head 3 against the platen roller 11 via the thermal transfer material 1 and the recording medium 2.

In FIG. 1, the thermal transfer material 1 and the recording material 2 are moving in the same direction, but for example, the recording material 2 is conveyed in the direction opposite to the arrow B direction, and the thermal transfer material 1 and the recording material 2 are conveyed. It does not matter even if 2 is moved in the opposite direction.

Now, in the thermal transfer recording method of the present invention, the thermal transfer material 1
And the recording medium 2 have a relative speed. In the example shown in FIG. 1, the thermal head 3 does not move, and the thermal transfer material 1 moves slower than the recording medium 2. That is, comparing the distance that the thermal transfer material 1 moves and the distance that the recording medium moves within the same time, the moving distance of the thermal transfer material 1 is shorter.
As a result, in this recording method, recording is performed as shown in FIGS.

As shown in FIG. 2, when the width of the heating element 3a of the recording head 3 in the heat-sensitive transfer material feed direction (arrow A direction) is set to 1, the first heat application is applied to the unused heat-sensitive transfer material 1 at l. It is carried out in size (Fig. 2). The heat-sensitive transfer material 1 comprises a support 1a and a heat-transferable ink layer 1b provided on the support 1a.

However, when the heat is applied for the second time, the recording medium 2 is indicated by the arrow B.
While the thermal transfer material 1 is moving in the direction 1, the thermal transfer material 1 is 1 / N with respect to the recording head 3 (N = 5 in FIG. 2; the value of N can be printed many times in the same portion of the thermal transfer material 1). However, the [l- (l / N)] portion of the heat-sensitive transfer material 1 is reused when it has already been applied with heat once (FIG. 3).

When heat is continuously applied in the horizontal direction in this way, only 1 / N of the heat-sensitive transfer material that receives heat from the second time onward is unused, and the rest is repeated 1 / N. The heat has already been applied (FIGS. 3 to 5). That is, the heat-sensitive transfer material is in the same state as when the same portion is used N times, and furthermore, it moves while rubbing the surface of the recording medium.

In the above example, the heat transfer material 1 is moved by l / N with respect to the recording head 3 by the second and third application of heat, but it is moved by less than 1 or l / N or more. In that case, the thermal transfer material 1 is saved. The most efficient transfer amount of the thermal transfer material 1 is 1 / N between the application of heat and the next application of heat.
This is the case when moving. The above N is 2 to 10, and further 3
~ 8 are preferred.

In the above description, an example in which the recording head 3 does not move is shown. However, even when the thermal head 3 moves, the moving distances of the thermal transfer material 1 and the recording medium 2 are set with the recording head 3 as a reference. If the distance from the recording head 3 is
It can be considered in the same manner as the example described with reference to FIGS.
That is, in the thermal transfer recording method of the present invention, the distance that the thermal transfer material 1 moves with respect to the recording head 3 is shorter than the distance that the recording medium 2 moves with respect to the recording head 3 within the same time. .

As is clear from the above description, the heat-sensitive transfer material used in the heat-sensitive transfer recording method of the present invention has a part which is heated once and a part which is heated a plurality of times in the heat-transferable ink layer. It is preferable that the thermal transferable ink layer has a thermal behavior that hardly changes even when the temperature reaches it. The present inventor conducted a double-density recording study using various heat-sensitive transfer materials and found that the melt viscosity at _{100 ° C.} η _{100 ° C.} (cps)
And the melt viscosity at _{150 ° C.} η _{150 ° C.} (cps), it was found that the thermal transfer material satisfying the relationship of the following formula (1) is effective for double-density recording.

Is larger than 0.05, the thermal behavior of the heat transferable ink layer is largely changed depending on the temperature, which is not preferable because the temperature of the recorded image is not uniform.

The melt viscosity in the present invention is a value measured by the following device and cone used.

Equipment Viscometer Rotobisco RV12 type (HAAKE (HA
AKE) Inc.) Cone RKI 0.3 One example of the heat-sensitive transfer material used in the heat-sensitive transfer recording method of the present invention has a heat-transferable ink layer 1b on a support 1a as shown in FIG. The thermal transferable ink layer 1b is transferred onto a recording medium by application of heat, and the melt viscosity of the thermal transferable ink layer 1b shows the relationship of the above formula (1). The heat transferable ink layer 1b contains a coloring material in a binder.

As the binder used for the thermal transferable ink layer 1b,
For example, waxes such as carnauba wax, lanolin wax, paraffin wax, sasol wax, microcrystalline wax, castor wax, stearic acid, palmitic acid, lauric acid, aluminum stearate, lead stearate, barium stearate, stearin Higher fatty acids such as zinc acidate, zinc palmitate, methyl hydroxystearate, glycerol monohydroxystearate or their metal salts, derivatives such as esters, polyamide resins, polyester resins, epoxy resins, polyurethane resins, acrylic resins (For example, polymethylmethacrylate, polyacrylic amide), vinyl acetate resin, polyvinylpyrrolidone and other vinyl resins, polyvinyl chloride resin (for example, vinyl chloride-vinyl chloride). Redene copolymers, vinyl chloride-vinyl acetate copolymers, etc.), cellulosic resins (eg methylcellulose, ethylcellulose, carboxycellulose etc.), polyvinyl-alcohol resins (eg polyvinyl alcohol, partially saponified polyvinyl alcohol etc.), petroleum-based Resin, rosin derivative, coumarone-indene resin, terpene resin, nopolak type phenol resin, polystyrene resin, polyolefin resin (for example, polyethylene, polypropylene, polypten, ethylene-vinyl acetate copolymer, etc.), polyvinyl ether resin , Polyethylene glycol resin, and one kind or a mixture of two or more kinds of elastomers, natural rubber, styrene butadiene rubber, isoprene rubber and the like can be used. The melting point or softening point of the above material is preferably 90 ° C. or lower.

As coloring materials, carbon black, nigrosine dye, lamp black, Sudan black SM, fast
Yellow G, Benzisin Yellow, Pigment Yellow,
India Fast Orange, Dolphin Red, Paranitroaniline Red, Toluidine Red, Carmine F8, Permanent Bordeaux FRR, Pigment Orange R, Resor Red 2G, Rake Red C, Rhodamine FB, Rhodamine B Rake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Green B, Phthalocyanine Green, Oil Yellow GG, The Pon Farst Yellow CGG,
Kayaset Y963, Kayaset YG, Sumiplast Yellow
GG, Zapon Farst Orange RR, Oil Scarlett, Sumiplast Orange G, Orazol Brown G, Zapon Farst Scarlett CG, Eisenspiron Red BEH, Oil Pink OP, Victoria Blue F
One or two of the known dyes and pigments such as 4R, Farstogen Blue 5007, Sudan Blue, Oil Pekotsk Blue
A mixture of two or more species can be used.

The amount of the colorant contained in the thermal transferable ink layer 1b is preferably 5 to 50%, more preferably 7 to 35%, based on the entire thermal transferable ink layer 1b.

The thermal transferable ink layer 1b may have a structure in which a plurality of thermal transferable ink layers are laminated in multiple layers. Further, as shown in FIG. 7, a transparent layer 1c may be provided on the thermal transfer ink layer 1b. The transparent layer 1c is provided, for example, to prevent the thermal transferable ink layer 1b from being unnecessarily transferred to a recording medium or to improve the transferability of the ink layer. It is preferable that the transparent layer 1c does not contain a coloring material, but it may contain it. When the transparent layer 1c contains a colorant, the content is 4.0% or less with respect to the transparent layer 1c. Furthermore, an adhesive layer 1d may be provided between the thermal transfer ink layer 1b and the support 1a. The adhesive layer 1d is, for example, a thermal transfer ink layer.
It is provided to improve the adhesion between the support 1a and the support 1a. Of course, both the transparent layer 1c and the adhesive layer 1d may be provided at the same time. The transparent layer 1c and the adhesive layer 1d may or may not satisfy the relationship of the above formula (1).

As the support 1a, for example, a plastic film such as polyimide, aromatic polyamide, polycarbonate, nylon or polyester film, or paper such as condenser paper is used. Further, it is preferable to provide a material having heat resistance and lubricity, such as a silicone resin, on the surface of the support 1 on the heated side as a back surface treatment.

The thickness of the support 1a is preferably 3 to 20 μm, and further 4 to
12 μm is desirable, but thin ones of 3 μm or less can be used as long as they have high strength and heat resistance. Also, an excessively thick support is inferior in thermal conductivity, which is not preferable.

The coating amount of the heat transferable ink layer is 5 to 40 g / dry coating amount.
m ² and more preferably 6 to 30 g / m ² . If the coating amount of the heat transferable ink layer is too small, a recorded image of sufficient density cannot be obtained,
On the contrary, if the amount is too large, the recording energy is increased and the transferability is deteriorated, which is not preferable.

In producing the heat-sensitive transfer material used in the present invention, the material selected from the above-mentioned viewpoint is, for example, toluene,
Dissolve in an organic solvent such as methyl ethyl ketone, isopropyl alcohol, methanol, xylene, mix the colorant, sufficiently disperse with a disperser such as a sand mill, and apply it on the support by a coating method such as bar coating or gravure coating. Good. Alternatively, the resin may be heated to a softening point or higher to disperse the colorant and then applied by so-called hot melt coating. Further, a resin or a coloring material may be applied as an aqueous emulsion by adding a dispersant such as an interfacial lubricant.

Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 The above materials were heated and dispersed by an attritor to obtain a thermal transfer ink.

This ink was provided on a 6 μm-thick polyester film having a back surface treatment of silicone resin using a wire bar so that the dry coating amount was 15 g / m ^2, and the thermal transfer material having the constitution shown in FIG. Got I.

Example 2 (heat transferable ink layer) (Transparent layer) The materials for the heat transferable ink layer were dissolved and dispersed using a sand mill to prepare a heat transferable ink. This ink was coated on a 6 μm-thick polyester film, which had been treated with a back surface of silicone resin, using a wire bar, and the coating amount after drying was
The heat transferable ink layer was coated so that the amount was 15 g / m ² .
Further, on the thermal transferable ink layer, the coating material after drying the material of the transparent layer using a wire bar is 3 g / m ²
And a thermal transfer material II having the structure shown in FIG. 7 was obtained.

Example 3 (Adhesive layer) (Thermal transfer ink layer) The material for the above adhesive layer is provided on a polyester film having a thickness of 6 μm, which is back-treated with a silicone resin, with a wire bar so that the coating amount after drying is 1 g / m ² to form an adhesive layer. did. This adhesive layer was cured by aging treatment at room temperature (25 ° C.) for 3 days. On the other hand, the material of the above-mentioned thermal transferable ink layer was dissolved and dispersed using a sand mill, and a wire bar was provided on the adhesive layer so that the coating amount after drying was 15 g / m ^2, and A thermal transfer material III having the structure shown in the figure was obtained.

Example 4 The above materials were dissolved and dispersed using a sand mill to obtain a thermal transfer ink. This ink was provided on a 6 μm-thick polyester film, which was back-treated with silicone resin, using a wire bar so that the coating amount after drying would be 15 g / m ^2, and the composition shown in FIG. A thermal transfer material IV was obtained.

Comparative Example 1 The above materials were dissolved and dispersed using a sand mill to obtain a thermal transfer ink. This ink was provided on a 6 μm-thick polyester film that had been subjected to a back surface treatment of silicone resin using a wire bar so that the coating amount after drying was 15 g / m ^2, and a single layer of ink was formed on the support. A thermal transfer material V having only layers was obtained.

Comparative Example 2 The above materials were dissolved and dispersed using a sand mill to obtain a thermal transfer ink. This ink was provided on a 6 μm-thick polyester film having a back surface treatment of silicone resin using a wire bar so that the coating amount after drying was 15 g / m ^2, and one ink layer was formed on the support. Thermal transfer material having only
Got VI.

Now, the inks of the thermal transferable ink layers used in Examples 1 to 4 and Comparative Examples 1 and 2 were dried to measure the melt viscosity, and the melt viscosity at 100 ° C. and 150 ° C. was measured by the above-mentioned apparatus. . The measurement results are shown in Table 1.

On the other hand, Canon's Huaximilli (trade name: Canonhoax 630) was partially modified to make a double-density recording Faximill device, and thermal transfer materials I to VI were loaded into this Faximilli device to form a recorded image on recording paper. The print density uniformity (presence or absence of voids in the paper) was evaluated. Second evaluation result
Shown in the table.

 The printing conditions are as follows.

Thermal head; 8 pel thick film type full multi-thermal head Thermal transfer material feed amount: 1/5 (N =
5) Feeding direction: Thermal transfer material and recording medium are feeding in opposite directions Printing speed: 25mm / sec Printing energy: 22mJ / mm ² [Advantages of the Invention] According to the present invention, various recorded advantages of conventional time-sensitive thermal transfer recording are not impaired, particularly, uniformity of density is excellent, and a recorded image excellent in cover ledge of the surface of a recording medium is obtained,
In addition, low running costs can be realized because the amount of thermal transfer material used is small.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of an apparatus for carrying out the recording method of the present invention, FIGS. 2 to 5 are partial side views showing an example of the recording method of the present invention, and FIGS. 6 to 8 are books. It is a partial side view showing an example of a heat-sensitive transfer material used in the recording method of the invention. 1 ... Thermal transfer material 2 ... Recording medium 3 ... Recording head 3a ... Heating element

Claims (1)

(57) [Claims] 1. A heat-sensitive transfer material having a heat-transferable ink layer having a melt viscosity satisfying the following formula (1) is used on a support, and the distance from the distance the recording material moves to the recording head within the same time is used. A thermal transfer recording method characterized in that the distance that the thermal transfer material moves with respect to the recording head is shorter. However, η _{100 ℃} is the melt viscosity at 100 ℃ (cps) η _{150 ℃} is the melt viscosity at 150 ℃ (cps)