JPH0692036A - Thermal transfer recording medium - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a thermal transfer recording medium capable of repeated transfer many times in thermal transfer recording of a thermal fusion method using a line head. [Structure] In a thermal transfer recording medium 10 for a line head having a support 1 and an ink layer 3, the ink forming the ink layer 3 contains an oil component.

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 capable of multi-time printing in thermal transfer recording using a line head.

[0002]

2. Description of the Related Art Thermal transfer recording is a recording method in which a thermal transfer recording medium is selectively heated according to image information and ink is transferred from the thermal transfer recording medium to a transfer medium such as recording paper.
Above all, thermal transfer recording of a thermal melting type in which ink is melt-transferred from a thermal transfer recording medium to a transfer target at the time of transfer is widely used. Further, as a heating means at the time of transfer, a line head is used in addition to a thermal head for serially printing.

An intermittent recording method is a useful recording method when performing thermal transfer recording using a line head. For example, when forming a recording image of A4 size by using a line head with 1728 elements in the reception recording of a facsimile, it is possible to print one line with four strobes from the relationship between the number of elements of the line head and the power supply capacity. Has been done.

By the way, the thermal transfer recording medium has conventionally been a one-time type which cannot be repeatedly used because once used for thermal transfer recording, the ink layer in that portion is completely transferred to the transferred body. However, in recent years, a multi-time thermal transfer recording medium that can be repeatedly used many times has been desired, and its development has been attempted. For example, as a multi-time thermal transfer recording medium, an ink layer is formed by sequentially stacking ink and a resin in which a filler is dispersed in a layered manner, and at the time of transfer, the layered ink layers are transferred one by one. Or an ink layer is formed by holding the ink in a porous resin layer, so that the ink in a molten state is partially transferred from the porous resin layer to the transfer target at the time of transfer, There has been proposed a device in which ink remains in the ink layer even after transfer.

[0005]

However, when intermittent recording is performed by using a line head, it is impossible to perform good repeated printing many times even if a conventional multi-time thermal transfer recording medium is used. There was a problem.
That is, when performing intermittent recording using the line head, first, the transferred material and the thermal transfer recording medium are superposed, and one line is divided into predetermined strobes for heating, and then the transferred material and the thermal transfer recording medium are separated. Since the first strobe of one line is printed, the transfer target and the thermal transfer recording medium are separated after heating the last strobe of the line. For this reason, when the first strobe is peeled off, the ink cools and is no longer in a molten state. Therefore, the adhesive force between the ink layer and the ink layer supporting layer is relatively large compared to the cohesive force of the ink in the ink layer. As a result, not only a proper amount of ink is transferred from the ink layer to the transfer target, but the ink layer is separated from the support layer and transferred to the transfer target. Therefore, it becomes impossible to perform printing many times.

As described above, in the thermal transfer recording using the line head, it is difficult to repeat the transfer a large number of times even if the conventional thermal transfer recording medium for multi-time is used. The reality is that only recording media are used.

The present invention is intended to solve the problems of the prior art as described above, and provides a thermal transfer recording medium capable of repeating a large number of times in thermal transfer recording of a thermal fusion system using a line head. The purpose is to do.

[0008]

The present inventor has made an ink constituting an ink layer of a thermal transfer recording medium used for thermal transfer recording of a thermal melting method contain an oil component,
While heating the first strobe to the last strobe of one line with the line head, it is effective to prevent the ink heated in the first strobe from being completely hardened even when it cools, This invention was completed.

That is, the present invention provides a thermal transfer recording medium for a line head having a support and an ink layer, wherein the ink forming the ink layer contains an oil component.

The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view of a thermal transfer recording medium 10 according to an embodiment of the present invention, in which a support 1, a conductive layer 2 and an ink layer 3 are sequentially laminated.

Here, it is preferable to use a heat-resistant support such as aramid or polyimide for the support 1 so that the support 1 does not shrink due to heat transfer and can withstand a large number of transfers. Further, in the case of using an electrically heat-sensitive type head as the line head, it is preferable to use a heat-resistant conductive support such as conductive aramid in which carbon is contained in aramid as the heat-resistant support.

As the conductive layer 2, for example, a metal film of gold, copper, aluminum or the like can be used. This conductive layer 2
May be formed as a vapor deposition film. Alternatively, they may be laminated via an adhesive. The conductive layer 2 is not necessarily required when a thermal head other than the heat-sensitive energization type is used as the line head, but the conductive layer 2 is provided in order to efficiently transfer the heat of the thermal head to the ink layer. It is preferable.

The ink layer 3 is a layer that holds an ink composed of a colorant and a binder resin, but in this case, the ink holding mode is not particularly limited. For example, the ink and the resin in which the filler is dispersed may be sequentially laminated in layers on the conductive layer 2, or the porous film may be impregnated with the ink. From the viewpoint of improving multi-time printability, it is preferable to hold the ink on the porous film. As the porous film, it is possible to use a resin film in which a resin such as polytetrafluoroethylene (PTFE), polypropylene, polyester, or high-density polyethylene is formed by a stretching method so that the porosity is 80%. In particular, a porous film obtained by biaxially stretching polytetrafluoroethylene (PTFE) is preferable.

The present invention is characterized in that the ink forming the ink layer 3 contains an oil component, so that even if the ink is cooled to some extent during transfer using the line head, the oil component is contained. The ink is prevented from completely solidifying, the ink layer and the transfer-receiving material are peeled off well, and the multi-time printability is improved. Here, various oils can be used as the oil component as long as they are liquid at room temperature. For example, one or more of fatty acids such as oleic acid, fatty acid esters, phthalic acid esters such as DOP, trimellitic acid esters, higher alcohols and natural animal and vegetable oils can be used in combination. Also, the content in the ink is
It is preferably 5 to 40% by weight. If it is less than 5% by weight, the effect of adding the oil component is not sufficiently exhibited, while 40
If the content is more than the weight, the problem of scumming tends to occur.

As the ink components other than the oil component, the same colorants, binder resins and softening agents as in conventional inks can be used.

For example, as the colorant, various pigments such as carbon black can be used.

Examples of the binder include waxes such as carnauba wax, paraffin wax, candelilla wax, wood wax, beeswax, ester wax and polyethylene wax, higher fatty acids such as stearic acid, palmitic acid and lauric acid, Higher alcohols or metal salts or ester derivatives thereof can be used.

As the softening agent, for example, resins such as petroleum resin, polyamide resin, polystyrene resin, styrene-butadiene copolymer, acrylic resin, ethylene-vinyl acetate copolymer, and oils such as mineral oil and vegetable oil are used. can do.

[0020]

According to the thermal transfer recording medium of the present invention, since the ink forming the ink layer contains the oil component, the ink becomes semisolid even if it is cooled to some extent at the time of transfer and is not completely solidified. Therefore, after the thermal transfer recording medium is superposed on the transfer target, the ink is transferred using the line head, and before the thermal transfer recording medium is separated from the transfer target, the transferred ink is completely cooled even if the transferred ink cools to some extent. It does not solidify and only becomes a semi-solid state, and therefore the adhesive force between the ink layer and the layer supporting the ink layer (in the case of the thermal transfer recording medium of FIG. 1, the adhesion between the ink layer and the conductive layer). Force) will be relatively stronger. Therefore, when the thermal transfer recording medium is peeled off from the transfer body, the ink layer is not peeled off and attached to the transfer body, and only an appropriate amount of ink in the ink layer is partially attached to the transfer body. Like Therefore, even a thermal transfer recording medium once used for transfer still has an ink layer, and multi-time printing is possible.

[0021]

EXAMPLES The present invention will be described in detail below based on examples.

Example 1 A thermal transfer recording medium having the layer structure shown in FIG. 1 was prepared. In this case, a conductive aramid film (3.6 kΩ / □) (manufactured by Toray Industries, Inc.) having a thickness of 10 μm is used as the support 1, and an aluminum vapor-deposited film having a thickness of 1000 Å is used as the conductive layer 2. Formed. As the ink layer 3, a porous film having a porosity of 99.5% and a thickness of 10 μm obtained by biaxially stretching polytetrafluoroethylene was impregnated with ink. In this case, as the ink, one having the following ink composition and ink characteristics was used.

(Ink composition) Carbon black 20% by weight Paraffin wax (manufactured by Nippon Seiro Co., Ltd., HNP-3WAX) 34% by weight Carnauba wax (manufactured by Toyo Petrolite) 8% by weight Dispersant: MEK 4% by weight Oil: DOP 34 wt% (ink characteristics) Melting point 65 ° C. Viscosity 30 cps / 65 ° C. Comparative Example 1 A thermal transfer recording medium was prepared in the same manner as in Example 1 except that an ink having the following composition and characteristics was used.

(Ink composition) Carbon black 20% by weight Paraffin wax (manufactured by Nippon Seiro Co., Ltd., HNP-3WAX) 53.2% by weight Carnauba wax 22.8% by weight Dispersant: MEK 4% by weight (ink characteristic) Melting point 65 C. Viscosity 1300 cps / 65.degree. C. Evaluation As shown in FIG. 2A, printing was performed using the thermal transfer recording medium 10 prepared in Example 1. That is, the thermal transfer recording medium 10 was superposed on the recording paper 4, and the heating element 6 of the head 5 of the line printer heated the recording paper 4 and the recording paper 4 and the thermal transfer recording medium 10 were separated at the separation angle θ. In this case, the printing conditions were as follows. Further, as shown in FIG. 3A, the thermal transfer recording medium 11 prepared in Comparative Example 1 was used to perform similar printing.

(Printing conditions) Printing width 75.8 mm Printing speed 4 nch / s Recording density 7.6 dot / mm Recording energy 15.7 mJ / mm ² As a result, when the thermal transfer recording medium of Example 1 was used, the peeling angle Even if θ is 0 degrees, the recording paper 4 and the thermal transfer recording medium 1
It was peeled off satisfactorily from 0, and as shown in FIG. 2B, only the ink in the printed portion was transferred to the recording paper. Then, printing could be repeated many times. On the other hand, when the thermal transfer recording medium of Comparative Example 1 was used, even if the peeling angle θ was 15 degrees, part or all of the ink layer adhered to the recording paper 4 as shown in FIG. As a result, the printing quality was degraded. Moreover, this thermal transfer recording medium could not be used any more repeatedly.

[0026]

According to the thermal transfer recording medium of the present invention, in thermal transfer recording of a thermal melting system using a line head, it is possible to repeat transfer a number of times.

[Brief description of drawings]

FIG. 1 is a sectional view of a thermal transfer recording medium of the present invention.

FIG. 2 is an explanatory diagram of a transfer state of an ink layer when printing is performed using the thermal transfer recording medium of the example.

FIG. 3 is an explanatory diagram of a transfer state of an ink layer when printing is performed using a thermal transfer recording medium of a comparative example.

[Explanation of symbols]

 1 Support 2 Conductive Layer 3 Ink Layer 4 Recording Paper 5 Head of Line Printer 6 Heating Element 10 Thermal Transfer Recording Medium

Claims (5)

[Claims] 1. A thermal transfer recording medium for a line head having a support and an ink layer, wherein the ink forming the ink layer contains an oil component. 2. The thermal transfer recording medium according to claim 1, wherein the ink layer is composed of ink held on a porous film. 3. The thermal transfer recording medium according to claim 1, wherein the ink forming the ink layer contains an oil component in an amount of 5 to 40% by weight. 4. The thermal transfer recording medium according to claim 1, which is used for intermittent thermal recording. 5. The oil component comprises at least one of fatty acid ester, phthalic acid ester, trimellitic acid ester, higher alcohol, and natural animal or vegetable oil.
4. The thermal transfer recording medium according to any one of 4 above.