JPH022082A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To prevent the release between a heat generating resistor layer and a conductive layer in the case of use in a thermal transfer printing system by constituting the conductive layer of a laminated structure consisting of the first conductive layer containing at least one metal selected from a specific metal group and the second conductive layer based on Al or an Al alloy. CONSTITUTION:The conductive layer provided on a heat generating resistor layer 12 has a laminated structure consisting of the first and second conductive layers 13, 14 and the first conductive layer 13 acts as the adhesive layer of the heat generating resistor layer 12 and the second conductive layer 14. The first conductive layer 13 is composed of a layer containing 60% or more of at least one metal selected from a group consisting of Ni, Cr, Fe, Co, Ru, Rh, Ta and In and the thickness thereof is set to 1,000Angstrom or less. The second conductive layer 14 is composed of a layer based on Al or an Al alloy and having a thickness of 500Angstrom or more. Since the first conductive layer acts as the adhesive layer of the heat generating resistor layer and the second conductive layer, no release is generated between the conductive layer and the heat generating resistor layer even when stress due to a heat shock or a sudden current supply phenomenon is applied at the time of printing recording.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thermal transfer recording medium used for converting electrical signals into thermal energy and transferring an ink image to a transfer material.

BACKGROUND ART Conventionally, when recording an image corresponding to a predetermined digital image signal on a recording medium, such as 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) thermal head transfer method (Japanese Patent Laid-Open No. 53-84735), 2) electrical transfer method in which the ink layer is energized (Image Electrophotography Society Journal: 198
2 years Vo1.11, ~α1, p3~9), 3) Current thermal transfer recording method using a print recording medium in which a heat generating layer and a return electrode are provided on an ink support of medium resistance (Japanese Patent Laid-Open No. 56-93585
4) An electric thermal transfer recording method has been proposed 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 the heat generated in the heat generating layer is utilized. has been done.

Among these recording methods, the electrical thermal transfer recording methods 3) and 4) have the advantages of relatively fast printing speed, no need to impart conductivity to the ink, and a high degree of freedom in selecting ink materials. Yes, and various proposals have been made. However, in these electrical thermal transfer recording methods, the ink support does not have anisotropic conductivity, so the dots spread, the leakage current is large, the energy efficiency is poor, or the applied current passes through the heat generating layer twice. This causes a lot of energy loss, and since the sliding contact is made twice with the needle electrode and the return electrode, there is also a lot of heat loss due to contact resistance. This method requires a certain degree of resistance in the conductive layer in the recording medium, and has drawbacks such as increased heat loss in the conductive layer.

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

Problems to be Solved by the Invention By the way, the conventionally proposed thermal transfer recording is made by laminating an anisotropic conductive layer, a heating resistor layer that generates heat upon input of an electric signal, a conductive layer, an ink peeling layer, and a heat-melting ink layer. The medium used is one that improves the same point in the conventional technology as described above, but when printing is performed using this thermal transfer recording medium, the heat generating resistor layer and the conductive layer are damaged due to the stress caused by the current flowing from the needle electrode. The problem was that peeling easily occurred during the process.

The present invention has been made in view of the above-mentioned problems in the conventional technology.

Therefore, an object of the present invention is to provide a thermal transfer recording medium in which peeling does not occur between the heating resistor layer and the conductive layer when used in a thermal transfer printing method.

Other objects of the present invention are to enable repeated print recording, high-speed printing, and high-density energy manual operation, to reproduce high-quality color images, and to record robust images with multiple gradations. The object of the present invention is to provide a thermal transfer recording medium that can perform print recording with high energy efficiency and low running cost.

Means for Solving the Problems The present inventors investigated the conductive layer in a thermal transfer recording medium having an anisotropic conductive layer, a heating resistor layer, a conductive layer, and a heat-melting ink layer. The inventors have discovered that the above-mentioned problems in the prior art can be solved by creating a laminated structure made of a specific material, and have 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 upon input of an electric signal, a conductive layer, an ink peeling layer, and a heat-melting ink layer, and The conductive layer is made of Ni, Cr, Fe, C
o, Ru, Rh, Ta.

60% of at least one selected from the group consisting of In
A! Alternatively, it is characterized by having a laminated structure with a second conductive layer containing an Al alloy as a main component and having a thickness of 500 Å or more.

FIG. 1 is a schematic cross-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-melting layer. This is an 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 current loss due to current conduction resistance when current is applied in the thickness direction, and also reduces heat loss and heat generation damage due to 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 it may be a layer in which conductive paths made of a conductive substance such as metal powder or conductive ceramic particles are formed in an insulating material such as ceramic or synthetic resin. You can cover it. In the thermal transfer recording medium of the present invention, when the anisotropic conductive layer is a layer consisting of a conductive isolated pattern, the heating resistor layer may have a function as a support; In the case of a conductive layer, the anisotropic conductive layer itself has a function as a support,
A thin film heating resistor layer may be formed on the negative side.

A conductive isolated pattern is a pattern in which a large number of microelectrodes isolated from each other like - are provided on one surface of a heating resistor layer as a support, and even if the size of each microelectrode is the same, May be different.

Further, the thickness of the microelectrode is 500 to 30 Ωm, preferably 10#2 or less.

The pattern area of each microelectrode is not particularly limited as long as each microelectrode is electrically isolated, and can be arbitrarily determined from the viewpoint of image dot transfer position accuracy and energy efficiency.
However, it is preferable that the pattern area be equal to or smaller than the area of one pixel electrode of the image signal applying electrode in the print recording head that is in pressure contact with the microelectrode, but in particular, the pattern area should be four-fifths or less. is preferred. Specifically, the pitch is 1μm to 5μm.
00 μm, preferably a pitch of 10 μm to 120 μm, and a circular, rectangular, or other polygonal shape with a diameter of 5 μm to 400 μm.

Further, the volume resistivity value of each microelectrode needs to be lower than the volume resistivity value of the heating resistor layer on which the microelectrode is provided, but preferably a value of 1/100 or less. has.

The materials constituting these microelectrodes include NCLJ, C
r, 5nSTa, T i , Zn, Au, Ag, Fe,
Metals such as AI, Pt, RuO2, S I C, WC, M
OS! 2. Conductive ceramics such as T i C,
Any material having electrical conductivity, such as polyacetylene or a polymer material containing a conductive substance dispersed therein, may be used. Specifically, the volume resistivity value is 10 Ω·cm or less, preferably 1o-2.
It is Ω·cm or less.

In the present invention, the microelectrodes can be created using any method such as vacuum evaporation, sputtering, photolithography, plasma CVD, and printing.

In the print recording medium of the present invention, the heating resistor layer on which the microelectrodes are provided also serves as a support for the print recording medium, and has a plate-like or It is belt-shaped and has a volume resistivity of 10-3 to 1o3Ω・c.
m, is preferred. The heating resistor layer is composed of a conductive film made of a heat-resistant resin (polyimide resin, polyimide amide resin, silicone resin, fluororesin, epoxy resin, etc.) in which conductive substances such as carbon and metal powder are dispersed. be done.

The conductive layer provided on the heat generating resistor layer has a laminated structure and consists of a first conductive layer and a second conductive layer,
The first conductive layer acts as an adhesive layer between the heating resistor layer and the second conductive layer. The first conductive layer includes Ni, Cr, Fe, Co
, Ru, Rh, Ta, and In, and can be formed by various sputter deposition methods or vacuum evaporation methods. In particular, it is preferable to use a high-frequency sputtering method because the film thickness can be made uniform and strong adhesion can be achieved.

The film thickness needs to be set to 1000 Å or less. When the film thickness becomes thicker than 1000, no adhesive effect can be obtained.

The second conductive layer laminated on the first conductive layer is Al or A
It is a layer having a thickness of 500 Å or more and mainly composed of l alloy, and can be formed by a vacuum evaporation method or various sputtering methods, but it is preferably formed by a vacuum evaporation method, which has a high deposition rate.

Further, a layer containing Al or an Al alloy as a main component is a very effective material in adhesion to an ink release layer provided thereon. Aluminum alloys include aluminum-based alloys such as Al-Ni alloys, Al-Ag alloys, and Al-Ni alloys.
-AC+ alloy etc. can be used.

The ink release layer is provided between the thermofusible ink layer and the second conductive layer. The ink release layer is a thin film having a low surface energy function, and basically has a critical surface tension lower than the surface energy of the recording paper, that is, the transfer material. For example, if the transfer material is plain paper,
The thin layer has a critical surface tension of 43 dynes/cm or less, preferably 40 dynes/cm or less. Further, when this critical surface tension is lower than the surface tension of the heat-fusible ink layer, a greater effect can be obtained in the transition phenomenon of the heat-fusible ink layer. The thickness of the ink release layer itself is 500 to 6μ.
Although it is preferable that the length of m1 is 3 #I or less, it is necessary to make the film as thin as possible. Examples of materials constituting the ink release layer include thermosetting silicone resin,
Fluorine-containing resin etc. can be used.

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

Function: The printing process using the thermal transfer recording medium of the present invention will be explained with reference to FIG. The thermal transfer recording medium 23 of the present invention is in the form of an endless belt, and has a transport roll 27.
27 for rotation. Reference numeral 21 denotes a print head, which is configured such that the recording paper 24 is brought into pressure contact with the thermal transfer recording medium 23 between the print head and the back roll 22. An image input signal from the print head is input in dynamic contact with a thermal transfer recording medium rotated by a conveyance roll, and is transmitted from the anisotropic conductive layer to the conductive layer via the heating resistor layer.

At this time, electricity-to-energy conversion is performed in the heating resistor layer, and the generated thermal energy is thermally propagated to the heat-melting ink layer through the conductive layer and the ink release layer, and the heat-melting ink is is melted and transferred onto recording paper. The thermal transfer recording medium 23 after printing is reproduced. That is,
The heat-melting ink is deposited by the ink regenerating device 25 and is uniformized by the temporary deposition roll 26 to be regenerated.

In the thermal transfer recording medium of the present invention, the conductive layer has a laminated structure consisting of a first conductive layer and a second conductive layer, as described above, and the first conductive layer has a heating resistor layer and a second conductive layer. Since it acts as a bond between the conductive layer and the conductive layer, it
Even if stress such as heat shock or sudden current flow phenomenon is applied, peeling will not occur between the conductive layer and the heating resistor layer.

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

Example 1 Cr was deposited on a carbon-dispersed conductive polyimide film with a surface resistance of 500 Ω and a thickness of 45 Ω by vacuum evaporation to form a 4000 Ω thick Cr film, and then photolithography was performed. A rectangular Cr pattern of 15IIIn square with a pitch of 20JIIri was formed on the entire surface by dry etching. Next, on the opposite side to the side on which the Cr pattern was formed, Ni was deposited as a film by high frequency sputtering at a substrate temperature of 200'C to form a first conductive layer with a thickness of 50 nm.

Subsequently, Al was deposited by vacuum evaporation at a substrate temperature of 250'.
A second conductive layer having a thickness of 1,000 layers was formed by vapor deposition under a C1 ultimate vacuum of 1 x 10-7 Torr.

Next, a thermosetting silicone resin was applied onto the second conductive layer made of AI and cured to form an ink release layer with a film thickness of 0.5#1 and a critical surface tension of 34 dynes/cm. Next, a colored polyester resin containing 7% by weight of pigment and having a melting point of 95°C was applied and dried to form a heat-melting ink layer with a thickness of 7%.

A needle electrode with a diameter of 60 pm was pressed onto the obtained thermal transfer recording medium, and pulses of 400 μs were applied at 10 V, 13 V, and 16 V.
Input with V, touch the recording paper on the back rubber roll,
Printing was performed at a contact pressure of 3 kg/cr/l.

As a result, a good transferred dot image was formed on the recording paper. In that case, no change was observed in the Ni--Al laminated conductive layer consisting 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 produced 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 was deposited using a vacuum evaporation method at a substrate temperature of 250° C. and a vacuum level of 1×1 O-7 TOrr to a film thickness of 1500. A 99.99% aluminum evaporated film was formed.

A printing experiment was conducted on the obtained thermal transfer recording medium under the same conditions as in Example 1, and the following results were obtained.
I was pissed.

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 351 IIrI by high-frequency magnetron sputtering at a substrate temperature of 25
The film was deposited at 0'C to form a tantalum nitride layer with a thickness of 2,000 yen. A resist film with a polka dot pattern of 10 μm in diameter and a pitch of 15 is formed on the entire surface of the tantalum nitride layer using a photolithography process. Next, the tantalum nitride layer is removed in areas where there is no resist film by dry etching using oxygen plasma. A conductive isolated pattern made of tantalum was formed.

Next, on the surface where the conductive isolated pattern is not formed, C
A first conductive layer having a thickness of 400 nm was formed by depositing r on the substrate by high frequency sputtering at a substrate temperature of 250°C. Next, A
1 by vacuum evaporation method at a substrate temperature of 300°C,
A second conductive layer having a thickness of 1200 nm was formed. Next, the silicone compound was gasified and polymerized in plasma to form an ink release layer with a film thickness of 1500 dynes/cm 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 heat-melting ink layer having a thickness of 1011 fr1.

A needle electrode of 40 mm was pressed into contact with the obtained thermal transfer recording medium, and voltages of 350μ5(7)V/L, 12V, 16V, and 2V were applied.
An input voltage of 0 V was applied, and printing was performed by contacting the recording paper on the back rubber roll with a contact pressure of 2.0 Kg/crA.

As a result, a good transferred dot image was formed on the recording paper. In that case, no change was observed in the Or-AI laminated conductive layer consisting 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 is deposited using the copper EB vacuum evaporation method.
The film was deposited at a substrate temperature of 250'C to form a Cu vapor deposited film with a film thickness of 2000.

A printing experiment was conducted on the obtained thermal transfer recording medium under the same conditions as in Example 1, and the following results were obtained.

Effects of the Invention In the thermal transfer recording medium of the present invention, since the conductive layer has a laminated structure as described above, it provides durability against heat shock and sudden current flow phenomena, and also has a large margin of printing conditions. This makes it possible to achieve stable printing heat generation, high-speed printing using short pulses, and dot area modulation due to input energy changes with high reliability. Therefore, by printing and recording using the thermal transfer recording medium of the present invention, multi-gradation, high-quality color images can be obtained at high speed and with high energy efficiency.

[Brief explanation of the drawing]

FIG. 1 is a 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... Heat generating resistor layer,
13... First conductive layer, 14... Second conductive layer, 15.
...Ink release layer, 16...Thermofusible ink layer, 21
...Print head, 22...Back roll, 23...
Thermal transfer recording medium, 24... Ink regeneration device, 25... Ink main device, 26... Temporary adhesion roll, 27... Conveyance roll.

Claims (4)

[Claims] (1) A thermal transfer recording medium formed by sequentially laminating an anisotropic conductive layer, a heating resistor layer that generates heat upon input of an electric signal, a conductive layer, an ink release layer, and a heat-melting ink layer, in which the conductive layer includes Ni, Cr, Fe, Co, Ru, Rh, Ta, In
a first conductive layer with a thickness of 1000 Å or less containing 60% or more of at least one selected from the group consisting of Al or Al;
A thermal transfer recording medium characterized by having a laminated structure including a second conductive layer having a thickness of 500 Å or more and containing an alloy as a main component. (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/cm
The thermal transfer recording medium according to claim 1, wherein the thermal transfer recording medium has a film thickness of 3 μm or less. (4) The anisotropic conductive layer consists of a conductive isolated pattern, and the conductive isolated pattern has a volume resistivity of 1/100 or less of the volume resistivity of the heating resistor layer, and a signal application electrode area of 5 2. The thermal transfer recording medium according to claim 1, having a pattern area of 4 times or less and a film thickness of 10 μm or less.