JP2696935B2 - 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 used for converting an electric signal into thermal energy and transferring an ink image to a transfer material.

2. Description of the Related Art Conventionally, when recording an image corresponding to a predetermined digital image signal on a recording medium, for example, plain paper, a recording method using a thermal transfer recording medium such as an ink donor film is widely known.

Such recording methods include, for example, 1) a thermal head transfer method (Japanese Patent Application Laid-Open No. 53-84735) and 2) an energization transfer method in which the ink layer is energized (Journal of the Institute of Image Electrophotography, Vol. 1, 1982).
1, No. 1, p3-9), 3) Energizing thermal transfer recording system using a print recording medium in which a heating layer and a return electrode are provided on a medium resistance ink support (JP-A-56-93585), 4) There has been proposed an energized thermal transfer recording method in which a return electrode is provided on the same side as the needle electrode, a current path to the return electrode is formed in the heat generating layer of the print recording medium, and heat generated in the heat generating layer is used.

Among these recording methods, the energized thermal transfer recording methods 3) and 4) have the advantages that the printing speed is relatively high, there is no need to impart conductivity to the ink, and the degree of freedom in selecting the ink material is high. There are various proposals. However, in such an energized thermal transfer recording method, since the ink support does not have anisotropic conductivity, dots spread, a large leak current occurs, energy efficiency is poor, or an applied current passes through the heating layer twice. Therefore, a lot of energy loss occurs, and since the sliding contact is performed twice with the needle electrode and the return electrode, a large heat loss due to contact resistance also occurs. There is a drawback that the conductive layer in the recording medium requires a certain amount of resistance and heat loss in the conductive layer increases.

In order to solve this drawback, various thermal transfer recording media have been proposed in which an anisotropic conductive layer made of a conductive isolated pattern is provided on a heating resistor layer or a support layer is an anisotropic conductive layer.

Problems to be Solved by the Invention By the way, conventionally, an anisotropic conductive layer, a heat-generating resistor layer that generates heat by input of an electric signal, a conductive layer, an ink release layer, and a thermal transfer formed by laminating a heat-meltable ink layer are proposed. Although the recording medium is to improve the problems in the above-mentioned conventional technology, when printing is performed using this thermal transfer recording medium, stress due to current flowing from the needle electrode causes
There has been a problem that separation easily occurs between the heating resistor layer and the conductive layer.

The present invention has been made in view of the above-described problems in the related art.

Accordingly, it is an object of the present invention to provide a thermal transfer recording medium that does not cause separation between a heating resistor layer and a conductive layer when used in a thermal transfer printing method.

Another object of the present invention is to enable repetitive printing and recording,
High-speed printing, high-density energy input is possible, high-quality color images can be reproduced, robust images with multiple gradations can be recorded, and energy-efficient printing can be performed. An object of the present invention is to provide a thermal transfer recording medium capable of performing printing at a running cost.

Means for Solving the Problems The present inventors, anisotropic conductive layer, heating resistor layer, conductive layer,
As a result of studying the conductive layer in a thermal transfer recording medium having a heat-meltable ink layer and the fact that the conductive layer has a laminated structure made of a specific material, the above-described problems in the conventional technology can be solved. They have found and completed the present invention.

That is, the thermal transfer recording medium of the present invention is formed by sequentially laminating an anisotropic conductive layer, a heating resistor layer that generates heat by input of an electric signal, a conductive layer, an ink release layer, and a heat-meltable ink layer, And the conductive layer is Ni, Cr, Fe, Co, Ru,
At least one selected from the group consisting of Rh and Ta
% Of a first conductive layer made of a metal layer containing not less than 1000% and a second conductive layer made of Al or an Al alloy having a thickness of not less than 500%.
It has a stacked structure with a conductive layer.

FIG. 1 is a schematic sectional view of the thermal transfer recording medium of the present invention. In the figure, 11 is a conductive isolated pattern, 12 is a heating resistor layer, 13 is a first conductive layer, 14 is a second conductive layer, 15 is an ink release layer, and 16 is a heat-meltable layer. The ink layer.

Next, each component of the thermal transfer recording medium of the present invention will be described in detail. The anisotropic conductive layer has the function of reducing the conduction loss due to the conduction resistance during conduction in the thickness direction, and also reducing the heat loss and damage due to the contact resistance between the needle electrode and the surface of the thermal transfer recording medium. It may be a conductive isolated pattern layer made of electrodes, or a layer in which a conductive path made of a conductive substance such as metal powder or conductive ceramic particles is formed in an insulating material such as ceramic or synthetic resin. There may be. In the thermal transfer recording medium of the present invention,
When the anisotropic conductive layer is a layer made of a conductive isolated pattern, the heating resistor layer may have a function as a support. The conductive layer itself may have a function as a support, and a thin-film heating resistor layer may be formed on one surface thereof.

The conductive isolated pattern is provided with a large number of microelectrodes uniformly isolated from each other on one surface of a heating resistor layer as a support, and the size of each microelectrode is the same, It may be different. The thickness of the microelectrode is
It is from 500 ° to 30 μm, preferably 10 μm or less.

The pattern area of each of the microelectrodes is not particularly limited as long as each is electrically isolated, and can be arbitrarily determined in terms of image dot transfer position accuracy and energy efficiency. The area of one pixel electrode of the image signal applying electrode in the print recording head is preferably equal to or smaller than that of the pixel electrode, and it is particularly preferable that the pattern area is equal to or less than 4/5. Specifically, pitch 1μm to 50
0 μm, preferably 10 μm to 120 μm pitch and 5 μm diameter
It is formed in a circular, rectangular or other polygonal shape of m to 400 μm.

Further, the volume specific resistance of each microelectrode is required to be lower than the volume specific resistance of the heating resistor layer on which the microelectrodes are provided, but preferably, a value of 1/100 or less is used. Have.

Materials constituting these microelectrodes include Ni, Cu, C
Metals such as r, Sn, Ta, Ti, Zn, Au, Ag, Fe, Al, Pt, RuO
₂ , conductive ceramics such as SiC, WC, MoSi ₂ , TiC, etc., polyacetylene, a polymer material obtained by dispersing a conductive material, and the like may be used as long as they have conductivity. , 10 Ω · cm or less, preferably 10 ⁻² Ω · cm or less.

In the present invention, the microelectrode can be formed by any method such as a vacuum evaporation method, a sputtering method, a photolithography etching method, a plasma CVD method, and a printing method.

In the print recording medium of the present invention, the heating resistor layer provided with the microelectrodes also serves as a support for the print recording medium, and is 1 μm to 100 μm, preferably 5 μm to 5 μm.
It is a plate or belt having a thickness of 0 μm,
It is preferable that the volume resistivity is 10 ⁻³ to 10 ³ Ω · cm.
The heating resistor layer is made of, for example, a conductive film made of a heat-resistant resin (polyimide resin, polyimide amide resin, silicone resin, fluorine resin, epoxy resin, etc.) in which a conductive substance such as carbon or metal powder is dispersed. Is done.

The conductive layer provided on the heating resistor layer has a laminated structure and includes a first conductive layer and a second conductive layer, and the first conductive layer is formed of the heating resistor layer and the second conductive layer. Acts as an adhesive layer. The first conductive layer is composed of Ni, Cr, Fe, Co, Ru,
At least one selected from the group consisting of Rh and Ta
%, And can be formed by various sputtering deposition methods or vacuum evaporation methods. In particular, it is preferable to use a high frequency sputtering method because the film thickness becomes uniform and strong adhesiveness can be exhibited. Its film thickness must be set to 1000 mm or less. If the thickness is more than 1000 mm, the adhesive effect cannot be obtained.

The second conductive layer laminated on the first conductive layer is Al or Al
A layer mainly composed of an alloy and having a film thickness of 500 mm or more, and can be formed by a vacuum evaporation method or various sputtering methods, but is preferably formed by a vacuum evaporation method with a high film formation speed. Further, a layer containing Al or an Al alloy as a main component is a very effective material in adhesiveness to an ink release layer provided thereon. Also, aluminum alloy
Aluminum-based Al-Ni alloy, Al-Ag alloy, Al
-Ni-Ag alloy or the like can be used.

The ink release layer is provided between the heat-meltable ink layer and the second conductive layer. The ink release layer is a thin film having a function of low surface energy, and is basically a recording paper, that is,
It has a critical surface tension lower than the surface energy of the transfer material. For example, when the transfer material is plain paper, it is a thin layer having a critical surface tension of 43 dynes / cm or less, preferably 40 dynes / cm or less. If the critical surface tension is lower than the surface tension of the hot-melt ink layer, a greater effect can be obtained on the transfer phenomenon of the hot-melt ink layer. The thickness of the ink release layer itself is 500Å to 6 μm,
In particular, it is preferably 3 μm or less, but it is necessary that the film be as thin as possible. As a material constituting the ink release layer, for example, a thermosetting silicone resin, a fluorine-containing resin, or the like can be used.

The heat-meltable ink layer provided on the ink release layer,
A resin obtained by dispersing a known dye or pigment such as carbon black in a thermoplastic resin having a melting point of 140 ° C. or lower is used. The thickness of the thin film of the heat-fusible ink layer is preferably set in the range of 1 to 15 μm. When the film thickness is less than 1 μm, the dot reproducibility decreases, and when the film thickness is more than 15 μm, the energy required for printing increases.

Operation The print recording process using the thermal transfer recording medium of the present invention will be described with reference to FIG. The thermal transfer recording medium 23 of the present invention is in the form of an endless belt,
It is supported so as to rotate. Reference numeral 21 denotes a print head, which is a recording paper between the print head and the back roll 22.
The heat transfer recording medium 23 is pressed against the heat transfer recording medium 23. The image input signal from the print head is input in a dynamic contact state to the thermal transfer recording medium rotated by the transport roll,
From the anisotropic conductive layer to the conductive layer via the heating resistor layer. At that time, electric-energy conversion is performed in the heating resistor layer, and the generated thermal energy propagates through the conductive layer and the ink peeling layer to the heat-meltable ink layer, and the heat-meltable ink according to the input signal. Is melted and transferred onto the recording paper. The thermal transfer recording medium 23 after printing and recording is reproduced. That is, the heat-meltable ink is adhered by the ink regenerating device 25, and the ink is reproduced by the uniform deposition roller 26.

In the thermal transfer recording medium of the present invention, the conductive layer has a laminated structure composed of the first conductive layer and the second conductive layer as described above, and the first conductive layer is formed of the heating resistor layer and the second conductive layer. Since it acts as an adhesive layer with the conductive layer, peeling does not occur between the conductive layer and the heating resistor layer even when a stress such as a heat shock or a sudden energizing phenomenon is applied during printing.

EXAMPLES Next, the print recording medium of the present invention will be described with reference to examples.

Example 1 Cr was deposited on a carbon-dispersed conductive polyimide film having a surface resistance of 500Ω and a thickness of 45 μm by a vacuum deposition method to form a deposited film having a thickness of 4000 mm, and then subjected to photolithography. 20μm pitch by dry etching
Thus, a rectangular Cr pattern of 15 μm square was provided on the entire surface. Next, Cr
Place Ni on the opposite side of the pattern
A first conductive layer having a film thickness of 50 ° was formed at a temperature of 100 ° C. by a high frequency sputtering method. Subsequently, Al is deposited by a vacuum deposition method at a substrate temperature of 250 ° C. and a degree of vacuum of 1 × 10 ⁻⁷ Torr,
A second conductive layer having a thickness of 1000 Å was formed. Next, a thermosetting silicone resin is applied on the second conductive layer made of Al,
By curing, an ink release layer having a thickness of 0.5 μm and a critical surface tension of 34 dynes / cm was formed. Next, a colored polyester resin having a melting point of 95 ° C. containing 7% by weight of a pigment was applied and dried to form a 7 μm-thick hot-melt ink layer.

A needle electrode having a diameter of 60 μm is pressed against the obtained thermal transfer recording medium, a pulse of 400 μs is input at 10 V, 13 V and 16 V, and the recording paper is brought into contact with the recording paper on the back rubber roll, and printing is performed at a pressure of 3 kg / cm ^2. Recordings were made.

As a result, a good transfer dot image was formed on the recording paper. In that case, no change was observed in the Ni—Al laminated conductive layer composed of the first conductive layer and the second conductive layer in the thermal transfer recording medium.

Comparative Example 1 A thermal transfer recording medium was prepared in the same manner as in Example 1. However, instead of forming the first conductive layer and the second conductive layer as the conductive layer, Al is deposited at a substrate temperature of 250 ° C. and a degree of ultimate vacuum of 1 × 10 ⁻⁷ Torr by a vacuum evaporation method to form a film. 1500
A 99.99% Al vapor deposited film was formed.

When a printing experiment was performed on the obtained thermal transfer recording medium under the same conditions as in Example 1, the following results were obtained.

Example 2 Tantalum nitride was deposited on a carbon-dispersed conductive polyimide film having a volume resistivity of 6 Ω · cm and a thickness of 35 μm by a high-frequency magnetron sputtering method at a substrate temperature of 250 ° C. to form a tantalum nitride layer having a thickness of 2000 mm. . By a photolithographic process, a polka dot resist film having a pitch of 15 μm and a diameter of 10 μm is provided on the entire surface of the tantalum nitride layer, and then the tantalum nitride layer in a portion without the resist film is removed by dry etching using oxygen plasma. A conductive isolated pattern was formed.

Next, on the surface where the conductive isolated pattern is not formed,
Cr is deposited by high frequency sputtering at a substrate temperature of 250 ° C,
A first conductive layer having a thickness of 400 ° was formed. Subsequently, Al was deposited at a substrate temperature of 300 ° C. by a vacuum deposition method, and a film thickness of 1200
Was formed. Next, the silicone compound was gasified and polymerized in plasma to form an ink release layer having a thickness of 1500 ° and a critical surface tension of 32 dynes / cm on the second conductive layer made of Al. Next, a pigment-dispersed polyester resin having a melting point of 97 ° C. was applied and dried to form a hot-melt ink layer having a thickness of 10 μm.

A 40 μm square needle electrode was pressed against the obtained thermal transfer recording medium, and a 350 μs pulse was input at 12 V, 16 V and 20 V, and was brought into contact with the recording paper on the back rubber roll, at a pressure of 2.0 kg / cm ^2. A print record was made.

As a result, a good transfer dot image was formed on the recording paper. In that case, no change was observed in the Cr-Al laminated conductive layer composed of the first conductive layer and the second conductive layer in the thermal transfer recording medium.

Comparative Example 2 A thermal transfer recording medium was prepared in the same manner as in Example 2. However, instead of forming the first conductive layer and the second conductive layer as the conductive layer, Cu was deposited at a substrate temperature of 250 ° C. by a copper EB vacuum deposition method to form a 2000-μm thick Cu deposited film. .

When a printing experiment was performed on the obtained thermal transfer recording medium under the same conditions as in Example 1, the following results were obtained.

Effect of the Invention In the thermal transfer recording medium of the present invention, since the conductive layer has a laminated structure as described above, durability is given to heat shock and a sudden energizing phenomenon, and printing conditions are also large. It is possible to realize a stable printing heat generation phenomenon, high-speed printing by short pulses, and dot area modulation by a change in input energy with high reliability. Therefore, if printing is performed using the thermal transfer recording medium of the present invention, a multi-gradation, high-quality color image can be obtained at high speed and with high energy efficiency.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a thermal transfer recording medium of the present invention, and FIG. 2 is an explanatory diagram of a thermal transfer recording method using the thermal transfer recording medium of the present invention. 11 ... conductive pattern, 12 ... heating resistor layer, 13 ... first conductive layer, 14 ... second conductive layer, 15 ... ink release layer, 16
... heat-fusible ink layer, 21 ... print head, 22 ... back roll, 23 ... thermal transfer recording medium, 24 ... ink regenerator, 25 ... ink regenerator, 26 ... assumed roll, 27 ...
... Transport rolls.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-84984 (JP, A) JP-A-63-35388 (JP, A) JP-A-63-94888 (JP, A) JP-A-63-88 94889 (JP, A) JP-A-63-151482 (JP, A) JP-A-1-281993 (JP, A)

Claims (4)

(57) [Claims] 1. A thermal transfer recording medium comprising an anisotropic conductive layer, a heating resistor layer that generates heat by input of an electric signal, a conductive layer, an ink release layer, and a heat-meltable ink layer, which are sequentially laminated.
The conductive layer is a metal layer containing at least one selected from the group consisting of Ni, Cr, Fe, Co, Ru, Rh, and Ta at 60% or more; A thermal transfer recording medium having a laminated structure of a second conductive layer having a thickness of 500 mm or more and mainly composed of an Al alloy. 2. The thermal transfer recording medium according to claim 1, wherein the heating resistor layer is made of a polyimide resin in which conductive particles are dispersed. 3. The ink release layer has a critical surface tension of 40 dynes / c.
2. The thermal transfer recording medium according to claim 1, wherein the thickness is 3 m or less. 4. An anisotropic conductive layer comprising a conductive isolated pattern, wherein the conductive isolated pattern has a volume specific resistance value of 1/100 or less of a volume specific resistance value of a heating resistor layer, and a signal application electrode area. 2. The thermal transfer recording medium according to claim 1, wherein the thermal transfer recording medium has a pattern area of 4/5 or less and a film thickness of 10 [mu] m or less.