JPH0313381A - Thermal recording method, medium and apparatus therefor - Google Patents

Abstract

PURPOSE:To form a printing image of high quality by a simplified process by applying a colorant to a part to be heated within a period when the part to be heated to which heat energy is applied imagewise of a heat-softenable layer is in a molten state or a low viscosity state. CONSTITUTION:A thermal recording medium 10 wherein a heat-softenable layer 12 is provided on a support 11 is fed by a feed means 1 and heat energy is imagewise applied to the heat-softenable layer of the thermal recording medium 10 by a heating means 2. Subsequently, within a period when a part 13 to be heated is in a molten state or a low viscosity state, a colorant 50 is applied to the part 13 to be heated by a colorant applying means 3. Further, if necessary, the colorant applied to a region other than the part 13 to be heated in the heat-softenable layer 12 of the thermal recording medium 10 is removed by a colorant removing means 4 and the colorant applied to the surface of the part 13 to be heated is fixed by a fixing means to form a printing image on the heat-softenable layer 12 of the thermal recording medium 10. As a heat- softenable substance, higher fatty acid, higher alcohol, higher fatty acid ester, amides or higher amines are designated other than waxes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal recording method, a thermal recording medium, and a thermal recording device, and more specifically, to forming a high-quality printed image through a simplified process. A highly reliable thermal recording method, a thermal recording medium that can be suitably used in this thermal recording method, is easy to manufacture, and has excellent production efficiency, and the aforementioned method using this thermal recording medium. The present invention relates to a thermal recording device that can be suitably used in.

[Prior Art and Problems to be Solved by the Invention] An electrophotographic printing process is known as a printing process that is widely applied in the fields of copying machines, laser beam printers, facsimiles, and the like.

This electrophotographic printing process has the advantage of not only excellent printing quality but also low noise because it is basically a non-impact type.

However, in the electrophotographic printing process, 1
Usually, there is a problem in that it requires a complicated process of charging, fogging, development, transfer and fixation.

Furthermore, in order to improve the reliability of the apparatus used in this type of printing process, it is necessary to simultaneously improve the reliability of each process.

Therefore, devices used in conventional electrophotographic printing processes have the disadvantage that periodic maintenance and inspection are essential.

The present invention has been made based on the above circumstances.

That is, an object of the present invention is to provide a thermal recording method that is capable of forming high-quality printed images through simplified steps and is highly reliable, and to provide a thermal recording method that can be suitably used in this thermal recording method. Another object of the present invention is to provide a thermal recording medium that is easy to manufacture and has excellent production efficiency, and a thermal recording device that can be suitably used in a thermal recording method using this thermal recording medium.

[Means for Solving the Problems] In order to solve the above problems, the present inventors have made extensive studies and found that a specific heat-sensitive recording medium having a non-transferable heat-softening layer on a support is used. According to the method described above, it is possible to form high quality printed images through a simplified process with high reliability.In addition, in this method, a specific thermal recording material that is easy to manufacture and has excellent production efficiency can be produced. The present invention has been arrived at by discovering that a medium can be suitably used, and that a highly reliable specific device can be suitably used in this particular method.

The structure of the invention according to claim 1 includes a heating step of applying thermal energy to the image quiz using a heat-sensitive recording medium having a non-transferable heat-softening layer on a support;
A coloring step of attaching a coloring material to the heated portion of the heat-softening layer to which thermal energy or imagewise is applied while the heated portion is in a molten state or a low viscosity state. It is a recording method, and the structure of the invention of claim 2 is a heat-sensitive recording medium characterized by having a non-transferable heat-softening layer on a support, and the structure of the invention of claim 3 includes at least the following: a means for conveying a thermosensitive recording medium; a heating means for imagewise applying thermal energy to the heat-softening layer of the thermosensitive recording medium conveyed by the conveying means; The heat-sensitive recording device is characterized by comprising a coloring material applying means for applying a coloring material to the heated portion of the heat-softening layer while the heated portion is in a molten state or a low viscosity state.

Each of the thermal recording method, thermal recording medium, and thermal recording apparatus of the present invention will be described in detail below.

11. Thermal Recording Method 11. In the thermal recording method of the present invention, the following thermal recording medium is used.

1. Thermosensitive Recording Medium 1. The thermosensitive recording medium of the present invention has at least a non-transferable heat-softening layer on a support.

It is desirable that the support has high dimensional stability, and furthermore, it is desirable that it has excellent heat resistance strength.

The materials include, for example, papers such as plain paper, condenser paper, laminated paper, and coated paper; resin films such as polyethylene, polyethylene terephthalate, polystyrene, polypropylene, and polyimide; composites of paper and resin films; and aluminum foil. Metal sheets such as the above are preferably used.

In addition, the thickness of the support is usually within the range of 10 gm or less, preferably 2 to 6 gm, when thermal energy is imagewise applied from the support side to the thermosoftening layer in the thermal recording method of the present invention. It is. In addition, when applying thermal energy imagewise to the heat-softening layer from the surface side of the heat-softening layer, is there any particular restriction on the thickness of the support? In order to have sufficient mechanical strength, it is usually 21.0 pm.
Above, it is preferably within the range of lO to ZOO)zm.

The heat-sensitive recording medium of the present invention has a non-transferable heat-softening layer described in detail below on one side of the support.

Naturally, the heat-softening layer contains at least a binder and a supercooled substance.

As the binder, for example, polyvinyl alcohol,
Vinyl acetate resins such as modified polyvinyl alcohol, vinyl acetate resin, vinyl acetate-maleic anhydride copolymer, and polyvinyl ether; Cellulose resins such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, acetyl cellulose, nitrocellulose, and acetyl butyl cellulose; polystyrene , thermoplastic resins such as polystyrene resins such as styrene-maleic anhydride copolymers, ethylene copolymers such as ethylene-vinyl acetate copolymers, and ethylene-vinyl chloride copolymers. For example, starches can also be used.

In any case, the binders may be used alone or in combination of two or more.

The supercooled substance is a supercooled substance that maintains a molten state or a low viscosity state for a certain period of time even at a temperature below the melting point or softening point when it is cooled from a molten or low viscosity state by heating above the melting point or softening point. It is a substance that exhibits cooling properties.

Therefore, in the heat-sensitive recording medium of the present invention, since the heat-softening layer contains the above-mentioned supercooling substance, even after thermal energy is imagewise applied to the heat-softening layer, the heated portion remains unchanged for a certain period of time. will maintain a molten state or a low viscosity state.

The supercooling substance is not particularly limited as long as it exhibits the above-mentioned supercooling property, and examples thereof include polyethylene glycol, polyethylene glycol monobehenate, polyoxyethylene monobehenyl ether, polyoxyethylene distearyl ester, and dicyclohexyl. phthalate,
Examples include benzotriazole and acetanilide. Further, for example, phenolic compounds, various waxes, aromatic compounds, etc. may be used as long as they exhibit supercooling properties.

The content of the supercooled substance in the thermosoftening layer is usually
It is 1 to 80% by weight, preferably 5 to 70% by weight. If this content is less than 1% by weight, supercooling properties may not develop in the heated portion of the thermosoftening layer. On the other hand, even if it exceeds 80% by weight, the corresponding effect may not be achieved.

The supercooled substance may be used by being dispersed in the binder, or if desired, it may be microencapsulated using a conventionally known microcapsule technique and contained in the thermosoftening layer.

The heat-softening layer 2 is further coated with a filler, if necessary.
It may contain known additives such as S-type agents and lubricants.

Examples of the filler include kaolin clay, alumina, diatomaceous, titanium oxide, talc, and mica.

Examples of the mold release agent include oils such as linseed oil and mineral oil, and silicones.

Examples of the lubricant include waxes such as paraffin wax, microx, and polyethylene wax;
Fatty acids such as stearic acid, myristic acid, behenic acid, etc., fatty acid amides such as stearylamide, valmitylamide, oleylamide, methylenebisstearamide, ethylenebisstearamide: lower alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids. , esters such as polyglycol esters of fatty acids: alkaline earth metal soaps such as monoalcohol, polyhydric alcohol, polyglycol, and polyglycerol.

These various additives may be used alone or
You may use two or more types in combination.

When the various additives described above are used, the content of these additives in the heat-softening layer is usually 40% by weight or less, preferably 1 to 30% by weight in total.

In any case, in the present invention, it is preferable that the heat-softening layer is colorless, or white or light-colored.If the color tone of the heat-softening layer is other than these, the heat-softening layer It may become difficult to distinguish between the color of the colorant deposited on the heated portion and the background color of the heat-softening layer, making it difficult to read the printed image formed by the method of the present invention.

The thermosoftening layer can be coated on the support by employing a water-based coating method, a coating method using an organic solvent, or the like.

Organic solvents that can be used in coating methods using organic solvents include: aromatic solvents such as toluene and xylene; alcohol solvents such as methanol and ethanol; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; acetic acid. Examples include ester solvents such as ethyl, cellosolves such as methyl cellosolve, butyl cellosolve and cellosolve acetate; special solvents such as dimethylformamide and dimethyl sulfoxide.

Moreover, a mixed solvent of these may be used.

In coating the thermosoftening layer composition on the support, any coating technique such as a reverse roll coater method, an extrusion coater method, a gravure coater method, a knife coater method, a bar coater method, etc. can be used. Can be adopted.

The layer thickness of the heat-softening coloring material layer is, for example, when applying thermal energy imagewise from the surface side of the heat-softening layer in the heat-sensitive recording method of the present invention, the upper limit of the layer thickness of the heat-softening coloring material layer There is no particular limit to 1, and it is usually at least O.Spm. In addition, in the thermal recording method of the present invention, when thermal energy is imagewise applied from the support side to thermally soften, it is usually 0.5 to 8 m, preferably 1.0 to 8 m.
It is 6.0 well.

Note that in the thermosensitive recording medium of the present invention, if desired,
For example, an appropriate intermediate layer may be provided between the support and the heat-softening layer, if desired, for the purpose of heat insulation between the support and the heat-softening layer and prevention of warpage in the heat-sensitive recording medium. It's okay.

-Step- As mentioned above, the method of the present invention includes a heating step and a coloring step.

Below, the heating process and the transfer process will be explained in detail separately.

In the heating step, thermal energy is imagewise applied to the thermosoftening layer of the thermosensitive recording medium.

In order to apply thermal energy imagewise, for example, both a serial thermal head and a line thermal head can be suitably used, but it is particularly preferable to use a line thermal head.

Further, 5. Application of thermal energy may be performed from the support side of the thermosensitive recording medium, or from the surface side of the heat-softening layer opposite to the support, especially the heat-softening layer. Imagewise application of thermal energy from the surface side of the thermosensitive layer suppresses the loss of thermal energy, eliminating the need to selectively thin the support and improving the productivity of the thermosensitive recording medium. It can be made expensive.

In the method of the present invention, the amount of thermal energy applied to the heat-softening layer may be determined as appropriate depending on the properties and purpose of the heat-sensitive recording medium used, but is usually 10 to 3
About 0 sJ/as2 is sufficient.

Note that when applying thermal energy from the surface side of the thermosoftening layer in the thermosensitive recording medium, the thermal energy may be applied directly to the thermosoftening layer, or if desired, the thermal energy may be phase-dissipated. It may be carried out through a suitable thin film medium as long as it does not cause an increase in .

Examples of the material for forming the thin film medium include films of polyethylene terephthalate, polycarbonate, polyimide, polyethylene, polypropylene, and the like.

Further, the thickness of the thin film medium is usually 10 μm or less. Use of the 0119 medium can prevent contamination of the thermal head and fusion of the thermosoftening layer to the thermal head.

In the method of the present invention, after applying thermal energy to the heat-softening layer of the heat-sensitive recording medium as described above, the coloring step described in detail is first performed.

In the coloring step, it is necessary to attach the coloring material to the heated portion of the heat-softening layer of the heat-sensitive recording medium while the heated portion is in a molten state or a low viscosity state.

That is, unless the heated portion of the heat-softening layer in the heat-sensitive recording medium is in a molten state or a low viscosity state, the colorant will not adhere to the heated portion.

Note that, as described above, the heat-softening property of the heat-sensitive recording medium used in the method of the present invention contains the supercooled substance, so after imagewise application of thermal energy, the heat-softening property is The heated portion maintains a molten state or a low viscosity state.

The coloring material used in the method of the present invention may be any coloring material as long as it has excellent fixing properties to the heated area, and examples thereof include conventionally known toners for electrophotography, soluble inks for thermal transfer, etc. I can do it.

That is, the electrophotographic toner usually contains a colorant, a binder, and an auxiliary agent.

Examples of the coloring agent include carbon black, copper phthalocyanine, sulfonamide derivative dye, benzidine derivative, and polytungstophosphoric acid.

Rhodamine B Lake, Carmine B6. Examples include quinacridone derivatives.

Examples of the binder include polystyrene resin, acrylic resin, epoxy resin, polyester resin,
Polyolefin resins, rubbers, ketone resins, rosin esters, rosin modified resins.

Examples include waxes.

The auxiliary agents include charge control agents such as organic acid salts and surfactants; fluidity improvers such as hydrophobic silica, graphite, and molybdenum disulfide; silicone resins, polyolefins,
Examples include anti-blocking agents such as paraffin wax and higher fatty acid esters.

The soluble ink for thermal transfer generally contains a coloring material and a heat-softening substance.

Specific examples of the thermosoftening substance include waxes such as vegetable wax, animal wax, petroleum wax, and mineral wax, and in addition to these waxes, higher fatty acids, higher alcohols, and higher fatty acids Examples include esters, amides and higher amines.

Examples of the coloring material include pigments such as inorganic pigments and organic pigments, and dyes.

Moekki'I! Pigments include titanium dioxide, carbon black, zinc oxide, Prussian blue, cadmium sulfide, iron oxides and chromates of lead, zinc, barium and calcium.

Examples of the organic pigments include azo, thioindigo, anthraquinone, anthanthrone, and triphenedioxazine pigments, vat dye pigments, phthalocyanine pigments, such as copper phthalocyanine and its derivatives, and quinacridone pigments.

Examples of the dye include acid dyes 2 direct dyes, disperse dyes, oil-soluble dyes, and metal-containing oil-soluble dyes.

Furthermore, for example, a known color former or color developer may be contained in the heat-softening layer of the heat-sensitive recording medium, and a color developer or color former may be used as the colorant.

In any case, the coloring material is applied to the heated portion of the heat-softening layer of the heat-sensitive recording medium.

Specifically, when using the electrophotographic toner as the coloring material, for example, a cascade phenomenon, a magnetic brush phenomenon, etc. may be used, or a non-magnetic coloring material may be electrostatically attracted onto the developing roller. The coloring material can also be applied to the heated portion. Further, when the above-mentioned soluble ink for thermal transfer is used as the coloring material, for example, the soluble ink for thermal transfer provided on a porous roll material or film is brought into contact with the thermo-softening layer of the thermal recording medium. Accordingly, the coloring material can be attached to the heated portion.

In the method of the present invention, after adhering the coloring material to the heated portion of the heat-softening layer of the heat-sensitive recording medium, 2. Usually, the colorant is attached to a portion of the heat-softening layer other than the heated portion. It is preferable to remove the attached coloring material.

As a means for removing the colorant adhering to areas other than the heated portion, known means such as a natural fall method, a magnetic brush method, a blow-off method, etc. can be suitably employed.

In addition, in the method of the present invention, if desired, after removing the coloring material that has adhered to a portion other than the heated portion, a step of fixing the heavy industry colorant that has adhered to the heated portion may be provided.

As a means for fixing the coloring material attached to the surface of the heated portion, known means such as a method using a heat roller, a method using a pressure roller, a method using a combination of a heat roller and a pressure roller, a flash fixing method, etc. Either of these can be suitably employed.

In the method of the present invention, a high quality printed image is stably formed on the surface of the thermosoftening layer of the thermosensitive recording medium through the simplified steps as described above and with high reliability. I can do it.

Next, the thermal recording device of the present invention will be explained.

-1 Thermal Recording Apparatus 11 For example, as shown in FIG. .1 heating means 2 for imagewise applying thermal energy to the thermosoftening layer 12 on the top of the thermosoftening layer 12; and heating portion 13 of the thermosoftening layer 12 to which thermal energy is imagewise applied by the heating means 2 to a molten state or It has a coloring material applying means 3 that applies the coloring material 50 to the heated portion 13 while it is in a low viscosity state.

The conveyance means 1 may be of any type as long as it can stably convey a heat-sensitive recording medium at a constant speed while maintaining a constant tension like a heat-sensitive recording medium. It is possible to use transport means. Also, the meandering of the thermal recording device and the thermal recording medium L! ! (
In order to prevent the occurrence of wrinkles in the paper, for example, rollers 20 or bars may be appropriately installed.

As the heating means 2, a thermal head having a heating resistor such as TaaN (RuO2) on a ceramic substrate can be suitably used.

For example, a toner roller can be suitably used as the colorant applying means 3.

In the thermal recording device of the present invention, while the heated portion 13 of the heat-softening layer 12 of the thermal recording medium U is in a molten state or a low viscosity state, the heated portion 1
It is necessary to attach a coloring material 50 to the surface.

Therefore, in the thermal recording device of the present invention, the heating means 2
For example, as shown in FIG. 1, when a thermal head is used as the heating means 2 and a toner roller is used as the coloring material applying means 3, the distance between
The distance between the thermal head and toner roller is typically:
It is 100 mm or less.

The heat-sensitive recording device of the present invention also includes, if desired, a colorant removing means 4 for removing a colorant applied to a portion of the heat-softening layer 12 other than the heated portion 13; A fixing means 5 for fixing the coloring material applied to the surface of the heating portion 13 can be provided.

For example, in the apparatus shown in FIG. 1, a blower is used as the colorant removing means 4, and a pressure roller is used as the fixing means 5.

Next, a case will be described in which a printed image is formed on the heat-sensitive recording medium of the present invention using the heat-sensitive recording device of the present invention.

As shown in FIG. 1, a thermal recording device having a heat-softening layer 12 on a support 11 is conveyed by a conveying means l (the conveying direction is indicated by an arrow in FIG. 1), and then heated. In the means 2, thermal energy is imagewise applied to the heat-softening layer 12 of the thermal recording medium.Next, in the colorant applying means 3, the heated portion 1.1 is in a molten state or a low viscosity state. In the meantime, the coloring material 50 is applied to the heated portion 13. Furthermore, if necessary, the colorant 50 applied to the heat-softening layer 12 of the thermosensitive recording medium at a portion other than the heated portion 13 is removed by the colorant removing means 4, and the fixing means 5 The coloring material applied to the surface of the portion 1 is fixed, and a printed image is formed on the heat-softening layer 12 of the heat-sensitive recording medium 10.

The printed image thus formed has excellent clarity and print density, and has high print quality.

[Example] Next, Examples of the present invention will be shown and the present invention will be explained in more detail.

(Example 1) After dispersing the heat-softening layer 12 described below using an assand grinder, a coating of 8 g/m'' was applied on plain paper using an air knife coating method, and a heat-softening layer with a thickness of 5 pm was applied. A thermosensitive recording medium with a softenable layer was prepared.

Using the obtained thermosensitive recording medium and electrophotographic toner [manufactured by Konica ■, 'U-Bix toner'],
Printing was performed on this heat-sensitive recording medium using a heat-sensitive recording device having the configuration shown in FIG. 1, and the printing quality of the obtained printed image and the reliability of the heat-sensitive recording device were evaluated. Here, fixing was performed by a flash fixing method.

In addition, the application of thermal energy is applied energy l mJ
/dat, thermal printer (prototype machine equipped with a line head, heating element density 8 d) under the condition of head pressure of 3 kg.
ot/-■).

Naturally 1f Li-based acetanilide...20 weight% polyvinyl alcohol...70 weight% calcium carbonate.
......10% by weight The printing quality and reliability were evaluated by evaluating the printing quality: image density and set 1 dot reproducibility as follows.

Furthermore, the meanings of the symbols in Table 1 are as follows.

O: Image density and fine line/dot reproducibility are good.

×: Poor image density and fine line/dot reproducibility.

Reliability: The difference between the print quality of an image formed in a low temperature, low humidity environment and the print quality of an image formed in a high temperature, high humidity environment was evaluated.

Furthermore, the meanings of the symbols in Table 1 are as follows.

○...The difference between the print quality of an image formed in a low temperature, low humidity environment and the print quality of an image formed in a high temperature, high temperature environment is small.

It was evaluated.

X: The difference between the print quality of an image formed in a low-temperature, low-humidity environment and that of an image formed in a high-temperature, high-humidity environment is small.

(Example 2) In Example 1, instead of the heat-sensitive recording medium prepared in Example 1, the following heat-softening layer composition was coated on a polyethylene terephthalate film with a thickness of 1100 JL using a hot-melt coating method.

The experiment was conducted in the same manner as in Example 1 except that a heat-sensitive recording medium having a heat-softening layer coated at a rate of 8 g/m'' and having a thickness of 5 am was used.

The results are shown in Table 1.

(Comparative Example 1) A printed image was formed by a conventional electrophotographic method using a Hiko photocopying machine, and the printing quality of the obtained printed image and the reliability of the copying machine were evaluated.

The results are shown in Table 1.

Paraoctylphenyl salicylate 20% by weight Carnauba wax 60% by weight Ethylene-vinyl acetate copolymer 10% by weight [Mitsui DuPont Chemical rEV ^40"] Calcium carbonate...
1O wt %■ As is clear from Table 1, the thermal recording method of the present invention using the thermal recording medium and thermal recording device of the present invention can stably produce high-quality printed images with high reliability. I've confirmed that I can get it.

[Effects of the Invention] According to the present invention, (1) using a heat-sensitive recording medium having a non-transferable heat-softening layer on a support, a heating step of imagewise applying thermal energy to the heat-softening layer; , a coloring process in which a coloring material is attached to the heated part while the heated part to which thermal energy is imagewise applied in a 1 mm maturation softening state is in a molten state or a low viscosity state, so it is simplified. It is possible to provide an industrially useful thermal recording method that can stably form high-quality printed images with high reliability through the steps described above.

(2) Furthermore, it is possible to provide a heat-sensitive recording medium that can be suitably used in the heat-sensitive recording method having the excellent advantages described above and has excellent productivity.

(3) Furthermore, it can be suitably used in the thermal recording method having the above-mentioned excellent advantages, and
We can provide a thermal recording device that is easy to maintain and inspect and is highly reliable.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of the configuration of a thermal recording apparatus of the present invention. ■...Transporting means, 2...Heating means, 3...Coloring material applying means, ■...Thermosensitive recording medium, 11...Support,
12... Thermosoftening layer, 13... Heated portion, 50...
・・Coloring material

Claims (3)

[Claims] (1) Using a heat-sensitive recording medium having a non-transferable heat-softening layer on a support, a heating step of imagewise applying thermal energy to the heat-softening layer; 1. A heat-sensitive recording method comprising the step of: attaching a coloring material to a heated portion while the heated portion is in a molten state or a low viscosity state to which imagewise imagewise application has been applied. (2) A thermosensitive recording medium characterized by having a non-transferable heat-softening layer on a support. (3) at least a means for conveying a thermosensitive recording medium, and a heating means for imagewise applying thermal energy to the thermosoftening layer of the thermosensitive recording medium conveyed by the conveying means;
a colorant applying means for attaching a coloring material to the heated portion while the heated portion of the thermosoftening layer is in a molten state or a low viscosity state to which thermal energy is imagewise applied by the heating means; A heat-sensitive recording device comprising: