JPS6025791A - Heat transfer material and transfer recording method using the same - Google Patents

Abstract

PURPOSE:To provide a thermal transfer material imparting a good recording image even to a recording medium inferior to surface smoothness, obtained by forming a thermal transfer layer wherein a powdery magnetic material and microcapsules each having a liquid - semi-solid oil agent are dispersed in a heat-meltable binder. CONSTITUTION:A powdery magnetic material (e.g., a ferromagnetic metal such as iron or cobalt or an alloy thereof having a particle size of 0.05-5mum) and microcapsules (each pref. having a particle size of 0.1-10mum and a coated resin thickness of 0.1-0.5mum) 5 each having an oil agent liquid - semi-solid at an atmospheric temp. are dispersed in a heat-meltable binder 4 such as carnauba wax. This dispersion is applied to a support 2 to obtain the objective transfer material 1 having a heat transfer ink layer 3 pref. having a thickness of 2-20mum formed thereto. A recording medium 6 is closely contacted with the ink layer 3 of this transfer material 1 and the ink layer 3 is heated in a pattern like manner while magnetic attraction force is acted on the whole to obtain a recording image 33 having a penetrated filling part 33a and having no breakage of an image to be printed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer recording method that provides good print quality even on recording media with poor surface slipperiness, and a thermal transfer material used therein.

In recent years, with the rapid development of the information industry, various information processing systems have been developed, and recording methods and devices suitable for each information processing system have also been developed and adopted. One such recording method is the thermal recording method.
The equipment used is lightweight, compact, noiseless, and has excellent operability and maintainability, and has recently been widely used.

However, among the recording papers used in thermal recording methods, ordinary thermal recording paper is a color-forming processed paper containing a color former and a color developer, so it is expensive, and records can be tampered with. It has disadvantages in that the recording has poor storage stability, such as being easily colored by paper or organic solvents, and the recorded image fading in a relatively short period of time.

In order to maintain the above-mentioned advantages of the thermal recording method and compensate for the disadvantages associated with the use of thermal recording paper, the thermal transfer recording method has recently been attracting particular attention. A heat-sensitive transfer material is prepared by melt-coating a heat-transferable ink consisting of a colorant dispersed in a heat-melting binder onto a support. A transfer ink image is formed on the recording medium according to the shape of the heat supply by superimposing it on the recording medium and transferring the melted ink layer to the recording medium by supplying heat with a thermal head from the support side of the thermal transfer material. It is something to do. According to this method, it is possible to maintain the above-mentioned advantages of the thermal recording method, use plain paper as a recording medium, and eliminate the above-described disadvantages associated with the use of thermal recording paper.

However, conventional thermal transfer recording methods are not without drawbacks. The reason is that in conventional thermal transfer recording methods, the transfer recording performance, that is, the printing quality, is greatly affected by the surface smoothness. Good printing is performed on highly smooth recording media, but when recording media with low smoothness are used, This means that the print quality deteriorates significantly. However, even when using paper, which is the most typical recording medium, highly smooth paper is rather special, and ordinary paper has various degrees of unevenness due to entangled fibers. Therefore, in the case of paper with large surface irregularities, the hot-melted ink cannot penetrate into the paper fibers during printing and only adheres to the convexities on the surface or the vicinity thereof, resulting in sharp edges of the printed image. The image may be missing, or part of the image may be missing, resulting in a decrease in print quality. Additionally, in order to improve printing quality, it is possible to use a heat-melting binder with a low melting point.
In this case, the thermal transfer ink layer becomes sticky even at relatively low temperatures, resulting in disadvantages such as decreased storage stability and staining of non-printed areas of the recording medium.

The main purpose of the present invention is to eliminate the drawbacks of the conventional thermal transfer recording method described above, maintain various thermal transfer properties, and improve surface smoothness as well as recording media with good surface smoothness. An object of the present invention is to provide a heat-sensitive transfer material capable of providing high-quality prints even on recording media with poor quality, and a heat-sensitive transfer recording method using the same.

According to the research of the present inventors, in order to achieve the above object, a penetrating ink consisting of magnetic powder and an oil agent that is liquid or semi-solid at room temperature is added to the heat-melting binder constituting the heat-transferable ink layer. It has been found that it is extremely effective to carry out a thermal transfer recording method under the action of magnetic attraction force using a thermal transfer material in which . That is, the heat-sensitive transfer material formed in this way,
When laminated with a recording medium through the thermal transferable ink layer, and applying a magnetic field from the back side of the recording medium and applying pressure with a platen, the thermal transferable ink layer is heated in a pattern.
The heat-melting binder melts or softens to lower its viscosity, and the heat-transferable ink layer is transferred to the recording medium, and the microcapsules are destroyed by pressure from the platen, releasing the ink contained therein. At about the same time, the transfer ink adheres to four parts of the surface of the recording medium due to the magnetic force acting on the magnetic powder in the ink. Furthermore, after that, the transfer ink penetrates into the structure of the recording medium due to the oil released by the destruction of the microcapsules. As a result of these actions, it is possible to prevent defects in printed images even on recording media with poor surface smoothness, and to improve printing quality.

The heat-sensitive transfer material of the present invention is based on such knowledge, and more specifically, the heat-transferable ink layer is formed on a support, and the heat-transferable ink layer contains a heat-melting binder containing: It is characterized by dispersing microcapsules containing magnetic powder and an oil agent that is liquid or semi-solid at room temperature. Further, in the thermal transfer recording method of the present invention, the thermal transfer material is laminated with a recording medium such that the thermal transferable ink layer thereof faces the recording medium, and the resulting laminate of the thermal transfer material and the recording medium is provided with: The thermal transferable ink layer of the thermal transfer material is heated in a pattern while exerting a magnetic attraction force from the thermal transfer material toward the recording medium, and after the recording medium and the thermal transfer material are separated, thermal transfer ink according to the heating pattern is applied onto the recording medium. It is characterized by leaving behind an image.

Hereinafter, the present invention will be described in further detail with reference to the drawings as necessary. “%” indicates quantitative ratio in the following descriptions.
"Parts" and "parts" are based on weight unless otherwise specified.

FIG. 1 is a schematic cross-sectional view in the thickness direction of an example of the most basic thermal transfer material of the present invention. That is, the heat-sensitive transfer material 1 is formed by forming a heat-transferable ink layer 3 on a support 2 that is usually in the form of a sheet (used to include a film).

As the support 2, conventionally known films and papers can be used as they are, such as relatively heat-resistant plastic films such as polyester, polycarbonate, triacetyl cellulose, nylon, and polyimide, cellophane, or parchment paper. can be suitably used. The thickness of the support is preferably about 2 to 15 microns when considering a thermal head as a heat source during thermal transfer, but for example, a heat source such as a laser beam that can selectively heat the thermal transferable ink layer is used. There are no particular restrictions when doing so. In addition, when using a thermal head, a heat-resistant protective layer made of silicone resin, fluororesin, polyimide resin, epoxy resin, phenol resin, melamine resin, nitrocellulose, etc. should be provided on the surface of the support that comes into contact with the thermal head. The heat resistance of the support can be improved by
Alternatively, support materials that could not be used conventionally can also be used.

The thermal transfer ink layer 3 is formed by dispersing microcapsules 5 containing magnetic powder and an oil agent in a heat-melting binder 4.

As the heat-melting binder 4, carnauba wax,
Waxes such as paraffin wax, Sasol wax, microcrystalline wax, and castor wax;
Higher fatty acids or their metal salts such as stearic acid, palmitic acid, lauric acid, aluminum stearate, lead stearate, barium stearate, zinc stearate, zinc palmitate, methyl hydroxystearate, glycerol monohydroxystearate i, Derivatives of esters, etc.; polyethylene, polypropylene, polyisobutylene, polyethylene wax, saturated polyethylene, polytetrafluoroethylene, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate' copolymer, ethylene-vinyl acetate copolymer, etc. Thermoplastic resins consisting of olefins alone or copolymers or derivatives thereof,
etc. are used. These heat-melting binders may be used alone or in a mixture of two or more.

As the magnetic material, materials generally known as ferromagnetic materials can be used arbitrarily; for example, metals of ferromagnetic elements such as iron, cobalt, nickel, and manganese, alloys containing these as main components, or magnetite, hematite, ferrite, etc. Examples include oxides of these elements as well as other compounds containing these ferromagnetic elements. As magnetic powder, those having an average particle size of 0.01 to 10 JL are generally used, preferably 0.05 to 5 #L.

Further, as the oil agent, a semi-solid material that is liquid at room temperature or has a softening point or melting point of 60° C. or lower is used. Specific examples of such oils include animal and vegetable oils such as cottonseed oil, rapeseed oil, camellia oil, castor oil, peanut oil, lanolin, beef tallow, lard, and whale oil.

Examples include motor oil, spindle oil, mineral oil such as dynamo oil, vaseline, glycerin, polyethylene glycol, dioctyl phthalate, monoolein, sorbitan trioleate, etc., as well as waxes, higher fatty acids or their metal salts, and esters within the range that satisfies the above conditions. derivatives such as, thermoplastic resins, etc. can also be used.

A magnetic fluid made by dispersing magnetic powder in an oil agent is also commercially available, such as the magnetic fluid "Marpo Magna FN-40J" manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.

To obtain microcapsules from the magnetic powder and oil described above, there is a method of mixing them to obtain permeable magnetic ink, then dispersing this in a solution of wall material resin, and spray drying the dispersion.) Conventional microencapsulation methods such as a phase separation method, a complex coacervation method, and an interfacial polymerization method may be employed as appropriate. Further, as the wall material resin, a known thermoplastic resin or thermosetting resin suitable for these microencapsulation methods is appropriately employed.

As the microcapsules, those having a diameter of 0.1 to 30IL, especially 0.1-LoJL can be preferably used, and the thickness of the coating resin is preferably in the range of 0.1 to 0.5mm. The ratio of each component in magnetic powder 1
Preferably, the range is 2 to 200 parts, particularly 5 to 100 parts, based on 0 parts of oil.

2 to 10 parts of such microcapsules
The coating solution obtained by mixing with 200 parts, preferably 5 to 100 parts of a heat-melting binder and diluting it with a dispersion medium (without a solvent if necessary) using a hot melt coater or a solvent coater, etc. The heat-sensitive transfer material 1 of the present invention is obtained by coating on a support 2 and drying to form a thermal transferable ink layer 3 having a thickness of 1 to 30 mm, preferably 2 to 20 mm.

In the above, the heat-melting binder 4 or the microcapsules 5 constituting the heat-transferable ink layer may contain a dispersant, a filler, and a coloring agent to increase the concentration of the heat-transferable ink layer or adjust its color tone, if necessary. It is also possible to contain agents and the like. As the colorant, various dyes, pigments, carbon black, etc. that are widely used in the fields of printing and recording can be used.

The planar shape of the thermal transfer material of the present invention is not particularly limited, but it is generally used in the form of a typewriter ribbon or a wide tape used in line printers. Furthermore, for color recording, heat-melting inks of several different tones may be prepared, and these may be applied in stripes or blocks to form a heat-sensitive transfer material.

Next, a thermal transfer recording method using the above thermal transfer material 1 will be described using the most typical thermal head as a heat source. FIG. 2 is a schematic cross-sectional view in the thickness direction of a thermal transfer material showing its outline.

That is, the recording medium 6 is brought into close contact with the heat-melting ink layer 3 of the heat-sensitive transfer material 1, and if necessary, a heat pulse is applied by the thermal head 8 while applying heat from the back side of the recording medium by the platen 7. The ink layer 3 is locally heated according to the desired printing or transfer pattern. The temperature of the heated part of the ink layer 3 increases and when it reaches a certain temperature, it softens or melts, and the pressure from the platen destroys the microcapsules, and the released ink turns into magnetic powder. The applied magnetic field causes the particles to adhere even to the recesses on the surface of the recording medium 7. Furthermore, the attached ink can penetrate into the inside of the fiber structure of the recording medium due to the penetrating power of the oil agent released from the microcapsules.

Therefore, even on a recording medium with poor surface smoothness, a recorded image 33 having the penetrating filling portion 33a and having no defects in the printed image and having good print quality can be obtained.

In order to apply a magnetic attraction force from the thermal transfer material 1 to the recording medium 6, any magnetic field generating means such as an electromagnet other than a permanent magnet may be used. The strength of the magnetic field is not particularly limited, but generally 400 degrees or more is used. Also,
It will be readily understood that other heat sources such as laser light can be used in addition to the thermal head as the heat source for thermal transfer recording.

As described in detail above, according to the present invention, a thermal transfer material in which a permeable magnetic ink consisting of magnetic powder and an oil agent is microencapsulated and dispersed in a thermal transfer ink layer is used, and magnetic field lines are By performing the thermal transfer recording method under the effect of heat transfer, it is possible to record with good print quality even on recording media with poor surface smoothness while maintaining good thermal transfer performance including storage stability of the thermal transfer material. be able to.

We can also expect improvements in recording sensitivity such as high-speed printing.

Furthermore, advantages such as being able to magnetically read recorded images are also obtained.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 15 parts of ferrite, 25 parts of rapeseed oil, and 5 parts of lecithin were kneaded using a triple roll to obtain a penetrating ink. 100 g of this ink was emulsified and dispersed in 400 g of a 2% aqueous gelatin solution using a homomixer at a stirring speed of 8000 rpm to obtain an emulsified dispersion having a particle size of 1 to 2 ILm. The pH of this dispersion was adjusted to 8 to 8 with an io% thorium carbonate aqueous solution.
After adjusting the pH to 9 and adding 50 g of urea-formalin prepolymer while stirring at a liquid temperature of 25° C., the pH was adjusted to 4 with acetic acid. Thereafter, the temperature of the emulsified dispersion was raised while stirring, and the temperature was raised at 30°C for 3 hours.

By keeping the mixture at 50° C. for 2 hours, a microcapsule dispersion having a urea-formalin resin wall around the penetrating ink particles was obtained. After cooling this dispersion.

Microcapsules containing 1-2 ILm of permeable ink were obtained by filtration. Polyethylene wax (softening point 9
5℃) 1 part, paraffin wax (softening point 70℃) 2
Approximately 1 part and 1 part carnauba wax with an attritor
The mixture was mixed by heating and stirring while maintaining the temperature at 00°C. Next, 16 parts of a petroleum solvent (trade name: Isopar H, manufactured by Esso) were added, heated to about 100°C, and cooled to room temperature with vigorous stirring to obtain a fine dispersion of ferrite/wax.

A coating solution obtained by mixing and stirring 20 parts of the fine dispersion of the wax and 4 parts of microcapsules is applied onto a polyester film with a thickness of 61 parts and dried to form a thermal transferable ink layer with a thickness of lOμ1m. A thermal transfer material having the following properties was obtained.

Comparative Example 1 part carbon black, 1 part polyethylene wax (softening point 95°C), paraffin wax (softening point 70°C)
) and 1 part of carnauba wax were dispersed and mixed using an attritor while heating to about 100°C, followed by petroleum solvent (trade name Isopar H, manufactured by Esso) 30
The mixture was heated to about 100° C. and cooled to room temperature with vigorous stirring to obtain Isopar H liquid in which carbon black/wax was finely dispersed.

Coating 61 parts of the above dispersion onto a polyester film,
After drying, a heat-sensitive transfer material having a transfer ink layer thickness of IOpm was obtained.

Using the two types of heat-sensitive transfer materials obtained as described above, recording was performed on three types of recording paper having different Bekk smoothness using a heat-sensitive transfer facsimile, and the resolution was evaluated. The upper resolution limits obtained using an electrophotographic test chart as a manuscript are summarized below.

To the town - Pound paper High quality paper ``Two-page paper''...'' Comparative example 3.6 pieces/as 4.5 trees/am 6.3 trees/
■Example 5.6 pieces/am 8.3 pieces per plate 6.3 pieces per piece■As is clear from the above results, the thermal transfer material according to the example of the present invention has a decreased smoothness of the recording paper. It is a thermal transfer material that does not require any paper quality, and there is very little reduction in resolution.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view in the thickness direction of an example of the thermal transfer material of the present invention, and FIG. 2 is a thermal transfer showing an embodiment of the thermal transfer recording method of the present invention using the thermal transfer material of FIG. FIG. 3 is a schematic cross-sectional view of the material in the thickness direction. l・- Sensitive thermal transfer material 2...Support 3...Thermal transferable ink layer 4...φ Heat-melting binder 5φ...Microcapsules 6 containing magnetic powder and oil agent...Recording medium 71. Platen 8 war... Netsuherado 33 fist - war ink recorded image (33a... Penetration filling part into the inside of the fiber structure)

Claims (1)

[Claims] 1. A thermally transferable ink layer is formed on a support, and the thermally transferable ink layer contains magnetic powder and an oil agent that is liquid or semi-solid at room temperature in a heat-melting binder. A heat-sensitive transfer material characterized by dispersing microcapsules. 2. A thermally transferable ink layer is formed on a support, and the thermally transferable ink layer includes microcapsules containing magnetic powder and an oil agent that is liquid or semisolid at room temperature dispersed in a heat-melting binder. A thermal transfer material made of The thermal transfer ink layer of the thermal transfer material is heated in a pattern while applying suction power,
A thermal transfer recording method characterized by leaving an image of thermal transfer ink corresponding to a heating pattern on a recording medium after separation of a recording medium and a thermal transfer material.