JPH06262860A - Ink sheet for thermal transfer recording - Google Patents

Abstract

PURPOSE:To provide an ink sheet always enabling stable printing reproduction of high image quality against the change of printing conditions such as a printing area, the heat accumulation of a thermal head. CONSTITUTION:An ink sheet 1 for thermal transfer recording is formed by providing an ink holding base material 3 having a large number of pores 4 or recessed parts filled with ink 5 obtained by adding a colorant such as pigment or a dye to a binder material such as hot-melt wax or an auxiliary material melted by heating or generating a change in viscosity under heating on the surface of a sheet like base material 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 recording system in which an image is formed on a recording paper by melting or softening ink by heating a thermal head or the like, and in particular, the thermal transfer recording used in this thermal transfer recording. The present invention relates to an ink sheet for recording.

[0002]

2. Description of the Related Art Here, a thermal transfer recording ink sheet used in a conventional thermal transfer printer will be described. Figure 7
FIG. 4 is a cross-sectional view showing the configuration of a conventional ink sheet, and the configuration of the conventional ink sheet 21 is configured by applying an ink layer 23 on a sheet-shaped base material 22.

The base material 22 is a sheet-shaped base material having heat resistance against heat during transfer, durability against mechanical load such as abrasion during conveyance of the ink sheet, and thermal conductivity. It is made of a material such as polyethylene terephthalate. The ink layer 23 is one in which a coloring material such as a pigment or a dye is added to a binder agent that melts or changes in viscosity when heated. Waxes are mainly used as the binder agent, and other softening agents and additives. Is further added, and carbon black or an organic-inorganic pigment or dye is used as a coloring material.

Next, a heating and transferring method when a conventional thermal transfer recording ink sheet is used will be described. Figure 8
(A) shows a heating process when a conventional thermal transfer recording ink sheet is used. By pressing the thermal head 24 against the platen roller 26, the ink layer coated surface of the ink sheet 21 is coated. And the recording paper 6 are brought into close contact with each other, and the thermal head 24
The heating element 25 is energized to generate heat.

As a result, the heat generated by the heating element 25 of the thermal head 24 is applied to the base material 22 of the ink sheet 21.
Area of the ink layer under the heating element (hereinafter,
This area of the ink layer is called a heating area)
The ink 28 in the heating area 27 is melted or its viscosity is changed. As a result, the ink 28 in the heating area 27 creates an adhesive force 30 with the recording paper 6.

FIG. 8B shows a process of peeling the ink sheet from the recording paper when using the conventional thermal transfer recording ink sheet. Heated as above,
Ink sheet 21 adhered to recording paper 6
Is conveyed by the conveying means in the direction of arrow A in close contact with the recording paper, and the ink sheet 21 and the recording paper 6 are separated from the separation guide 32 in the above-described conveying process.

At this time, as described above, in the ink layer 28 in the heating area which is heated and adheres to the recording paper, the cohesive force 33 of the ink itself with the surrounding unheated ink 29.
However, since the conveyance torque of the conveyance means (not shown) and the adhesive force between the recording paper and the cohesive force are larger than the cohesive force, an ink layer shearing force is generated between the ink layer in the heated region and the ink layer in the unheated region. The ink 34 separated from the sheet and transferred is transferred onto the recording paper 6.

[0008]

As described above, according to the conventional ink sheet for thermal transfer recording, it is possible to reproduce a high-quality image with a simple device configuration. However,
In the above heating process, the ink in the heated area causes adhesive force to the recording paper by heating, but it is partially affected by the cohesive force of other unheated ink and variations in the surface condition of the recording paper. Then, the adhesive force is reduced, and the force for shearing the ink at the time of peeling is insufficient, resulting in a transfer failure such as an insufficient transfer amount and a thin print dot.

On the other hand, when the transfer area is large, contrary to the above phenomenon, the heat storage property of the ink layer in the heated region affects other unheated ink, resulting in an increase in the transfer area and a secondary transfer. Transfer defects such as tailing in the scanning direction occur. Therefore, there is a problem that these transfer defects have a great influence on the print quality of an image reproduced.

Therefore, an object of the present invention is thermal transfer recording which always enables stable and high quality printing reproduction against the influence of ink cohesive force during heating, surface condition variation of recording paper and transfer area. To provide an ink sheet for use.

[0011]

In order to solve the above-mentioned problems, a thermal transfer recording ink sheet of the present invention is provided with a sheet-like base material having a large number of minute holes or recesses and the inside of the minute holes or recesses. In addition, the ink is prepared by adding a colorant such as a pigment or a dye to a binder agent made of hot melt wax or the like or an auxiliary material that melts or changes viscosity when heated.

[0012]

By configuring the ink sheet for thermal transfer recording as described above, when heated by a heating means such as a thermal head, the ink that is in a heated state and has melted or changed its viscosity is stored in the minute holes or minute recesses. Since they exist independently of each other, only the ink in the heated state can generate the adhesive force to the recording paper without being affected by the cohesive force and heat storage of the other inks in the unheated state. Even when separating the ink sheet and recording paper,
Since it is not affected by the cohesive force and heat storage of other unheated ink, only the ink that has generated the adhesive force to the recording paper is transferred, the change in the area to be transferred, the ink during heating Even if there are changes such as cohesive force and variations in the surface condition of the recording paper, only the ink in the minute holes or minute recesses existing in the heated area is transferred onto the recording paper, resulting in poor transfer of ink such as insufficient or excessive transfer of ink. Is prevented from occurring.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the thermal transfer recording ink sheet of the present invention. The thermal transfer recording ink sheet 1 of the present invention can be used in a recording apparatus similar to the conventional thermal transfer recording ink sheet. The configuration is such that an ink holding base material 3 having an infinite number of minute holes 4 is provided on the surface of a sheet-like base material 2, and the binder agent is colored in the minute holes 4 of the ink holding base material 3. The ink 5 is formed by adding a material.

Here, the base material 2 is a sheet-shaped base material having heat resistance against heat during transfer, durability against mechanical load such as abrasion during transport, and thermal conductivity. Is made of a single material or a composite material such as capacitor paper, polyester, polypropylene, polycarbonate, polymide, polyethylene terephthalate (PET).

The thickness of the base material 2 can be appropriately changed according to the material, but is preferably 2 to 15 μm.
Is. The ink holding base material 3 is a sheet-like base material having heat resistance against heat during transfer, durability against mechanical load such as abrasion during transport, and thermal conductivity, like the base material 2. Examples of the material include capacitor paper, polyester, polypropylene, polycarbonate, polymide, polyethylene terephthalate (PET), etc., or a single material or a composite material.

The thickness of the ink holding substrate 3 can be appropriately changed according to the material, but is preferably 2
Is about 15 μm. The inner diameter of the fine holes 4 provided in the ink holding substrate 3 and the pitch between the fine holes can be set arbitrarily, but preferably the inner diameter is 1 to 40 μm.
m, pitch 1.5 to 50 μm.

The ink 5 is made by adding a coloring material such as a pigment or a dye to a binder agent mainly containing wax that melts or changes its viscosity by heating. Examples of the material include beeswax, carnauba wax and wood. Natural waxes such as wax, paraffin wax, micro wax,
Paraffin wax, ester wax, etc.
There are higher fatty acids, higher alcohols, higher amides, esters, etc., and a heat-melting binder agent is formed by further mixing a heat-melting resin or the like, and as other additives, a softening agent, and There are additives. As an example of the color material, carbon black or organic / inorganic pigment or dye is selected according to monochrome printing or color printing.

Next, the printing process using the thermal transfer recording ink sheet of the present invention will be described. FIG. 2 shows a state during heating of the thermal transfer recording ink sheet of the present invention, in which a thermal head 7 composed of a plurality of heating elements 7b is pressed against a platen roller 8 on a substrate 7a, The ink sheet 1 and the recording paper 6 are brought into close contact with each other, and the heating element 7b of the thermal head 7 is energized to generate heat according to an input image, whereby the heat generated by the heating element 7b is transmitted to the base material 2 of the ink sheet. The ink 10 that is heated and is filled in the micropores in the heating region 9 under the heating element
By heating the ink, the ink 10 filled in the minute holes in the heating region 9 melts or changes its viscosity. As a result, the ink 10 filled in the minute holes in the heating region 9 has an adhesive force 11 with the recording paper 6.
At this time, the ink 12 filled in the micropores in the adjacent unheated area has the ink holding substrate 3 between the filled ink 10 in the heated area 9 and the filled ink 12 in the unheated area.
Is present, the effect is blocked.

FIG. 3 is an explanatory view showing a state in which the thermal transfer recording ink sheet of the present invention is conveyed and moved onto the heating element of the thermal head at the time of the above heating. In the ink sheet according to the embodiment of the invention, only the micropores existing in the heating region 9 of the heating element of the thermal head are heated, and a change in melting or a change in viscosity occurs due to heating. At this time, since all the inks 5 exist independently in the micro holes 4, the influence of the filled ink 5 in the micro holes 4 outside the other heating area is blocked by the ink holding substrate. Become.

Next, FIG. 4 shows a process at the time of peeling from the thermal transfer recording ink sheet of the present invention, and at the time of peeling the ink sheet 1 and the recording paper 6 which is one embodiment of the present invention. The ink 10 that has been heated as described above and that has been filled in the minute holes in the heating area that has become in the adhesive state with respect to the recording paper 6 is conveyed in the direction of arrow A by the conveying means in the state of close contact with the recording paper, Peeling guide 13 in the peeling process
The ink sheet 1 and the recording paper 6 are separated from each other. At this time, in the ink 10 in the micropores in the heated area, the influence of the ink layer shearing property between the ink 10 in the micropores in the surrounding unheated state is affected by the ink holding substrate 3 between the inks.
Since the ink 10 in the minute holes in the heated area is already separated by, the ink 14 is transferred onto the recording paper 6 by the adhesive force 11 to the recording paper, and is heated by the thermal head on the recording paper. An image of only the area is reproduced.

This is the ink 10 in the heated micropores.
Since the ink 12 in the micropores that has not been heated is physically blocked by the ink holding base material 3 between the micropores, the permeation and adhesion to the recording paper accompanying the melting of the ink are in other non-melted states. It is performed arbitrarily without being affected by ink. Further, at the time of peeling, the ink in the adhesive state with respect to the recording paper can be transferred with a sharp shearing property without being affected by the other ink in the non-adhesive state.

FIG. 5 is a schematic diagram showing a transfer state of one dot of ink of the thermal head heating element transferred as described above, and a plurality of transfer is made in the transfer area 16 of one dot of the thermal head heating element. Since the ink 14 is transferred, and the area of each transfer ink 14 is the same as the area of the micropores of the ink holding substrate, a transfer failure due to heat accumulation of the ink such as tailing occurs and print quality is improved. In addition to the deterioration, the image corresponding to one dot in the conventional thermal transfer is composed of a plurality of transfer inks, so that it is possible to obtain the effect of improving the resolution.

FIG. 6 is a schematic explanatory view showing another embodiment of the thermal transfer recording ink sheet of the present invention. The structure of the thermal transfer recording ink sheet 17 which is another embodiment of the present invention is a sheet. An ink 20 formed by providing a plurality of minute recesses 19 on the surface of a sheet-shaped ink holding substrate 18 and adding a coloring material to a binder agent in the minute recesses 19.
It is configured by filling. Here, the ink holding base material 17 is a sheet-shaped base material made of the same material as the base material 2 and the ink holding base material 3 of the thermal transfer recording ink sheet 1 described above, and the thickness thereof depends on the material. However, the thickness is preferably 2 to 20 μm.

The depth, the inner diameter and the pitch between the minute recesses 19 can be appropriately changed according to the material of the ink holding substrate and the ink to be filled, but the depth is preferably 4 to 6 μm. , Inner diameter 1 to 40 μm, pitch 1.
It is 5 to 50 μm. The ink 20 filled in the minute recesses 19 is the same as the ink 5 used in the thermal transfer recording ink sheet 1 described above. Here, the ink sheet 18 which is another embodiment of the present invention is also used in the recording method shown in FIG. 2 described above, and the same effect can be obtained.

[0025]

[Effect] In the thermal transfer recording ink sheet of the present invention, all of the ink applied to the ink sheet is formed in each of the minute holes or minute recesses, so that melting or viscosity change occurs during heating. The ink that permeates or adheres to the recording paper in the state of being unaffected is not affected by other ink in the non-heated state, and similarly, when the ink sheet and the recording paper are peeled off, Since the ink adhered to the recording paper is not affected by the other ink in the non-adhesive state, it is possible to transfer the ink in an area equal to the area of the minute holes or minute recesses.

Therefore, when the ink sheet for thermal transfer recording of the present invention is used, it is possible to always maintain a constant ink transfer amount for transfer by filling the ink in the minute holes or minute recesses, and always It is possible to reproduce an image with stable quality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a thermal transfer recording ink sheet of the present invention.

FIG. 2 is an explanatory diagram showing a state of the thermal transfer recording ink sheet of the present invention during heating.

FIG. 3 is an explanatory diagram of a state in which the thermal transfer recording ink sheet of the present invention is moved to a heat generating area.

FIG. 4 is an explanatory diagram showing a state at the time of peeling of the thermal transfer recording ink sheet of the present invention.

FIG. 5 is a schematic view showing a transfer state per dot of a heating element in the thermal transfer recording ink sheet of the present invention.

FIG. 6 is a cross-sectional view showing another embodiment of the thermal transfer recording ink sheet of the present invention.

FIG. 7 is a cross-sectional view of a conventional thermal transfer recording ink sheet.

FIG. 8 is an explanatory diagram of a recording method in a conventional thermal transfer recording ink sheet.

[Simple explanation of symbols]

 1 Ink Sheet for Thermal Transfer Recording 2 Base Material 3 Ink Holding Base Material 4 Micropores 5 Ink

Claims (1)

[Claims] 1. A sheet-shaped base material having a large number of micropores or recesses, and an ink containing a coloring material added to a binder agent that melts or changes viscosity when heated in the micropores or recesses. Characteristic thermal transfer recording ink sheet.