JP2581124B2 - Transferr for thermal recording - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer member for thermal transfer recording of an energization type, and more particularly, to an ink used in a fusion type or sublimation type thermal transfer recording of an energization type. The present invention relates to a transfer member such as a ribbon and an ink sheet.

[Prior Art] A thermal transfer recording of an energization method, which is one of the non-impact recording methods, is a transfer body having a basic configuration including a conductive base film and an ink layer (an intermediate layer between the base film and the ink layer). Is used to melt the fusible ink in the ink layer or to sublimate the sublimable ink by Joule heat generated when an electric current is passed through the conductive film, and the ink is applied to recording paper or the like brought into contact with the ink layer. Is a recording method for transferring and printing. This energized thermal transfer recording has the advantage that no noise is generated with respect to a mechanical impact printer.Furthermore, the thermal transfer recording method in which a transfer body is heated by a thermal head, which is one of the same non-impact recording methods, is used. Even in comparison, it has the advantage that high-speed recording and high-quality recording are possible in principle. However, to date, energetic thermal transfer recording is only commercially available on some typewriters.

[Problems to be Solved by the Invention] The reason that the spread of energized thermal transfer recording has been prevented is as follows.
Conventionally, the base film of the transfer body is mainly made of polycarbonate, so that heat resistance and mechanical strength are insufficient, and high-speed recording, downsizing of the apparatus, and reduction in printing cost cannot be realized. Is big.

In order to improve the problem of the transfer body, for example, Japanese Patent Application Laid-Open
Japanese Patent Application No. -120495 proposes a transfer member for heat-sensitive recording of an energization type using an aromatic polyamide film having good heat resistance and mechanical strength. On the other hand, aromatic polyamides are generally more expensive than polycarbonates and the like. Therefore, when an aromatic polyamide is used as a base film, it is desirable to use a thinner film in order to reduce the running cost of the recording apparatus. In view of the above, the characteristics of the aromatic polyamide cannot be sufficiently brought out unless a thin-leaf base film is used.

However, the aromatic polyamide film containing a large amount of carbon black has high strength but is brittle and vulnerable to tearing, so that the transfer body may be cut off from minute scratches generated at the edge of the slit or at the time of transfer recording. There was a problem that it easily occurred.

For example, if a narrow ink ribbon is manufactured by slitting, increasing the slit speed will only produce a ribbon with a flaw at the end, and if this is used for transfer recording, ribbon breakage will occur frequently. Therefore, there is a problem that the cost of the transfer member must be increased.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems described above and to provide a transfer body for thermal recording in which the slit property and the running property during the transfer recording are improved in the thermal transfer recording of the energization type.

[Means for Solving the Problems] The present invention relates to a heat-sensitive recording transfer member having an ink layer provided on one surface of an aromatic polyamide film containing 10 to 40 (wt%) of carbon black. Young's modulus in the longitudinal direction (Ym), Young's modulus in the width direction (Y
t) satisfies the formulas (1) and (2), Yt ≧ 400 (kg / mm ² ) (1) 1.05 ≦ Ym / Yt ≦ 2.00 (2) The F5 value in the longitudinal direction is 10 (Kg / mm ² ) As described above, the present invention is characterized by a heat-sensitive recording transfer member having a heat shrinkage stress of 2.0 (Kg / mm ² ) or less at 100 to 250 ° C.

In the thermal transfer recording of the energization type using the transfer body for thermal recording of the present invention, the ink layer surface of the transfer body is arranged so as to overlap the recording paper (or image receiving paper), and the recording is performed while the return electrode is in contact with the film side. A voltage is applied by bringing a current-carrying head having a structure in which recording electrodes are arranged in one or a plurality of rows into contact with a portion where the recording is performed. At this time, the film at the position of the recording electrode generates heat, and the heat causes the ink to be melt-transferred to the recording paper side in the case of fusible ink, and sublimates the ink in the case of sublimable ink to be fixed on the recording paper for recording. It is.

Those consisting of aromatic polyamide and polymer containing a repeating unit represented by the general formula _{HN-Ar 1 -NHOC-Ar 2} -CO 70 mol% or more of the present invention is preferred. Here, Ar ₁ and Ar ₂ contain at least one aromatic ring and may be the same or different, and representative examples thereof include the following.

Also, part of the hydrogen on these aromatic rings are halogen (especially chlorine), a nitro group, an alkyl group of C ₁ -C ₃ (especially methyl), such as alkoxy groups C ₁ -C ₃ It may be substituted with a substituent. Also, X is _{-O -, - CH 2 -,} -
SO _2- , -S-, -CO- and the like. These are included in the form of homopolymer or copolymer.

The aromatic polyamide of the present invention may be blended with a lubricant, an antioxidant, other additives, and other polymers to the extent that the physical properties of the film are not impaired.

The carbon black in the present invention is not particularly limited as long as it has conductivity, but is preferably furnace black or acetylene black. Carbon black which has been subjected to a surface treatment for improving electric conductivity may be used. Further, these carbon blacks preferably have a specific surface area of 5 m ² / g to 1000 m.
² / g, particularly preferably from 10m ² / g~950m ² / g, average primary particle size of preferably 5 nm to 500 nm, especially 10nm~100nm
The carbon purity is preferably 90% or more, more preferably 97% or more.

The amount of carbon black added is based on the total weight of the film
It is 10 to 40% by weight, preferably 15 to 35% by weight. If it is less than 10 wt%, the conductivity will be low and the film will not generate heat.
Conversely, if it exceeds 40 wt%, the conductivity will be too high and it will be difficult to convert to Joule heat in the film, the film temperature will not rise, the mechanical properties of the film will deteriorate, and the film will tear and wrinkle frequently, making it practical for use. Become intolerable.

In the aromatic polyamide film of the present invention, the Young's modulus (Ym) in the longitudinal direction (MD) and the Young's modulus (Yt) in the width direction (TD) of the film must satisfy the following two formulas, It is. Here, the longitudinal direction corresponds to the traveling direction of the transfer body when the transfer body is used in a ribo shape or a sheet shape, and the width direction is a direction perpendicular to this. When Yt is less than 400 (Kg / mm ² ), the stiffness of the transfer body in the width direction (stiffness)
Insufficiency of wrinkles easily causes wrinkles, which may cause the transfer body to be cut during the production of the transfer body (coating, slit, etc.) or transfer recording, and further, the contact with the current-carrying head becomes non-uniform, thereby deteriorating the recording quality. . In the present invention, Ym / Yt is 1.05
Although it is 2.00 or less, it has been found that good slit properties can be secured only by slightly breaking the balance of Young's modulus in this way. This is presumably because tension is applied only in the longitudinal direction at the time of slitting, so that a slightly larger Ym allows the transfer body to run smoothly and to come into contact with the cutting blade smoothly, so that a small scratch does not occur in the cut edge. Therefore, when the transfer body after the slit is used for transfer recording, the cut is small, and this is a particularly remarkable effect in a carbon black-containing aromatic polyamide film which is weak in tearing. However, if Ym / Yt exceeds 2.00, the transfer body will not run smoothly again, and the contact state with the current-carrying head will also deteriorate, and the recording quality will deteriorate, which is not desirable.

The F5 value in the longitudinal direction of the aromatic polyamide film of the present invention is 10 (Kg / mm ² ) or more, preferably 12 (Kg / mm ² ) or more. If it is less than 10 (Kg / mm ² ), the deformation due to the tension at the time of manufacturing the transfer body or at the time of transfer recording is large, and the slitting property and the contact with the energizing head are deteriorated, so that the recording efficiency and the recording quality are lowered.

The heat shrinkage stress in the longitudinal direction of the aromatic polyamide film of the present invention is 2.0 (Kg / mm ² ) or less at 100 to 250 ° C.
Preferably it is 1.0 (Kg / mm ² ) or less. 2.0 heat shrinkage stress
(Kg / mm ² ), the transfer member is deformed by the contraction force of the film during transfer recording, and the contact state with the energizing head is deteriorated, and the running state of the transfer member becomes unstable. Cuts easily occur.

Further, the aromatic polyamide film of the present invention preferably has a longitudinal strength of 12 (Kg / mm ² ) or more and an elongation of 10% or more,
More preferably, the strength is 15 (Kg / mm ² ) or more and the elongation is 15% or more.

The thickness of the aromatic polyamide film of the present invention is 1 to 20.
μm is preferable, and 2 to 10 μm is more preferable. If it is less than 1 μm, the strength is insufficient and it cannot be put to practical use. If it exceeds 20 μm, local heat cannot be applied due to large thermal diffusion, so that clear transfer cannot be performed and it is not suitable for high-speed recording.

The moisture absorption of the film of the present invention is preferably 4% by weight or less, more preferably 2% by weight or less. If it is more than 4 wt%, the electric resistance value changes depending on the humidity, or the moisture at the time of recording foams to lower the recording quality.

Next, the ink layer in the present invention is not particularly limited,
Specifically, a fusible ink or a sublimable ink can be used. The ink contains a coloring component and a binder component as main components, and if necessary, a softener, a flexible agent, a smoothing agent,
A dispersant, a surface forming agent, and the like are configured as additive components.
The thickness of the ink layer is 0.2 to 20 μm, preferably 0.5 to 10 μm
It is.

As the binder component, well-known waxes such as carnauba wax, paraffin wax, and ester wax, cellulose-based resins, vinyl-based resins, and various polymers having a low melting point are useful. Organic or inorganic pigments or dyes may be used, but are not limited thereto.

Next, a method for producing the aromatic polyamide film of the present invention will be described. The polymer is N-methylpyrrolidone (NM
P), dimethylacetamide (DMAc), hexamethylphosphoramide (HMPA), dimethylformamide (DM
It can be produced by adding a monomer of acid chloride and diamine to an organic solvent such as F), tetramethylurea, and γ-butyrolactone, and performing low-temperature solution polymerization, or interfacial polymerization using an aqueous medium. It can also be produced by adding a catalyst to isocyanate and carboxylic acid in the above-mentioned solvent. When a polymer solution obtained by polymerizing acid chloride and diamine as a monomer is used as it is as a stock solution,
Since hydrogen halide is generated, it is dissolved in an inorganic base such as calcium hydroxide, lithium carbonate, calcium carbonate or a hydrate thereof, ammonia, or an organic base such as ethylene oxide, propylene oxide, or triethylamine or diethanolamine. Sum up
It is necessary to prevent the adverse effect of hydrogen halide in the subsequent film forming process. The neutralized salt formed by this neutralization acts as a dissolution aid for the polymer and enhances the solubility of the polymer, but is further separated into halides of alkali or alkaline earth metals such as lithium chloride, lithium bromide and calcium chloride. May be added.

Depending on the type of the polymer and the type of the copolymerization component, a dissolution aid is not necessary, or a stable solution can be obtained even when the dissolution aid is less than the amount of the neutralizing salt. In some cases, the amount of the polymer and the dissolution aid can be appropriately controlled by adding the isolated polymer to a solvent.

The polymer can be isolated by throwing a polymer solution polymerized in an organic solvent into water or the like to reprecipitate it, or by washing and drying the polymer produced by interfacial polymerization.

Carbon black is sufficiently dispersed in an organic solvent or a small amount of a polymer solution in advance, and then added to the film forming stock solution.
There is a method of directly adding to a stock solution for film formation.

The polymer concentration in the film forming stock solution adjusted as described above is 2
About 40% by weight is preferable. When a salt formed by neutralization or an inorganic salt as a dissolution aid is contained, it is preferable to form a film by a wet method or a dry-wet method. When a film is formed by a wet method, a method is employed in which the undiluted solution is directly extruded from a die into a film-forming bath, or once extruded onto a support such as a drum and the support is introduced into the wet bath. This bath is generally composed of an aqueous medium, and may contain an organic solvent, an inorganic salt or the like in addition to water. But in general the water content
The bath is usually used at a temperature of 0 to 100 ° C. to extract salts and organic solvents contained in the film. Further, stretching is performed in the longitudinal direction of the film. The film discharged from the bath is then dried, stretched, and heat-treated, and these treatments are generally performed at 100 to 500 ° C.

When a film is formed by a dry-wet method, the undiluted solution is transferred from a die to a drum,
Extruded onto a support such as an endless belt to form a thin film,
Next, the solvent is scattered from the thin film layer and dried until the thin film has a self-holding property. Drying conditions are generally room temperature to 300
℃, within 60 minutes. After the dry process, the film is peeled from the support, introduced into the wet process, desalted and desolvated in the same manner as in the wet process, and further stretched, dried and heat-treated to form a film.

Depending on the type of polymer or the distribution ratio of the copolymerized unit, the polymer may be dissolved in an organic solvent without an inorganic salt,
In that case, it is possible to form a film by a dry method. Of course, the film may be formed by a wet method or a dry-wet method as described above.

When using this dry process, the drum,
Alternatively, a film which has been dried on an endless belt or the like and has self-holding properties is peeled off from these supports and stretched in the longitudinal direction of the film. Further, drying, stretching, and heat treatment are performed. These treatments are generally performed at 150 to 500 ° C.

The film formed as described above is subjected to stretching and heat treatment during the film forming process so that mechanical properties, thermal properties, and electrical properties fall within the scope of the present invention. Stretch ratio is 0.9 to 0.9
The ratio within 3.0 (area ratio is defined as a value obtained by dividing the area of the film after stretching by the area of the film before stretching. 1 or less means relaxed) improves the conductivity and improves the mechanical properties. It is preferable in maintaining characteristics and thermal characteristics. When the area ratio is larger than 3.0, the mechanical properties are improved, but the conductivity is remarkably deteriorated, and the heat resistance is also deteriorated.

Next, an ink layer is formed on the base film of the present invention obtained as described above. If necessary, a pretreatment such as a corona treatment or a glow treatment may be performed. The inks include those as described above, and can be formed by a general coating method such as hot-melt coating on one surface of the film or a solution dissolved in a solvent, such as gravure, reverse, or a slit die. .

The basic structure of the transfer body for thermal recording of the present invention comprises the above-described base film and ink layer, but between the film and the ink layer (referred to as an intermediate layer) or transfer for the purpose of further improving printability. A conductive layer, for example, Al, Au, Ag, Ni, Cr, Co, Zn, Sn, Mo, W,
Alternatively, these alloys, oxides, and nitrides
{Preferably, 400 to 3000}. Providing a conductive layer on the intermediate layer is very effective in locally increasing the current density from the current-carrying head, and it is more preferable to use Al as the intermediate layer. Providing a conductive layer on the side of the current-carrying head is preferable because the contact electric resistance between the film and the current-carrying head is reduced and recording energy is effectively used. Further, the present invention is not impeded by providing a layer other than the conductive layer on the intermediate layer side, for example, a release layer, a lubricant layer, a heat-resistant layer, or the like together with or without the conductive layer.

[Uses] The transfer body for thermal recording of the present invention thus obtained is a general typewriter, an output of a computer, a facsimile,
It can be suitably used for energized thermal transfer recording when printing or image printing is performed in a word processor, video printer, or the like. Further, the shape can be used as a general typewriter ribbon shape or a wide sheet shape according to each recording apparatus.

[Effect of the Invention] The transfer body for thermal recording of the present invention uses a carbon black-containing aromatic polyamide film having specific mechanical properties and heat shrinkage stress properties as a base film.
Even when the film is thinned, the slitting property at high speed is good, and wrinkles and cuts can be prevented during the production of the transfer body and at the time of transfer recording, and the contact state with the energizing head can be kept good. Clear recording is possible. Further, by reducing the thickness of the base film, it is possible to reduce the running cost of energized thermal recording, increase the recording speed, and improve the quality.

[Method for Measuring Characteristics] The method for measuring characteristic values according to the present invention is as follows.

(1) Young's modulus, F5 value Test width 10 (mm), test length 50 (m)
m), the film was pulled at a pulling speed of 300 (mm / min), and the Young's modulus was calculated from the relationship between film elongation and stress.

Further, the tensile stress when the film was stretched by a length of 5% was converted to the stress of the cross section 1 (mm ² ) of the film, which was defined as F5 value.

(2) Heat shrinkage stress A sample is cut out so that the test width is 10 mm and the test length is 100 mm.
Apply an initial load of 0.25Kg / mm ² and keep constant length. This is heated up to 250 ° C. at a heating rate of 10 ° C./min in a heating furnace, and the stress is written on a chart. The shrinkage stress is determined with the zero point before the initial load is applied.

[Examples] The present invention will be described with reference to examples.

Example 1 8.56 kg of 2-chloro-P-phenylenediamine and 9.85 kg of 4,4'-diaminodiphenylsulfone were dissolved in distilled N-methylpyrrolidone (NMP) in a jacketed stirring tank. The solution was cooled to 10 ° C., 20.30 kg of terephthalic acid chloride was added, and the mixture was stirred for 2 hours to carry out polymerization. Next, calcium hydroxide was added in the same amount as the generated hydrogen chloride for neutralization to obtain a polymer solution having a viscosity of 900 poise (30 ° C.) and a polymer concentration of 9% by weight. The intrinsic viscosity of the polymer was 2.9.
Then add carbon black to final film weight of 30
wt% and stirred well to obtain a homogeneous solution.

This solution was cast on a stainless steel endless belt and dried with hot air at 150 ° C. Next, the film having self-holding property was continuously peeled off from the belt and introduced into a water tank to extract residual solvent and inorganic salts. Further, moisture drying and heat treatment were performed in a tenter at 280 ° C. to contain carbon black. An aromatic polyamide film was obtained. During this step, the film was stretched 1.12 times in the machine direction (MD) and 1.00 times in the width direction (TD). Table 1 shows the characteristic values of the obtained film.

Next, an ink layer having the following composition was applied to one side of the above film to a thickness of 5 μm by a hot melt coating method using a heating roll.

Carnauba wax 35 parts Ester wax 33 parts Carbon black 17 parts Polytetrahydrofuran 12 parts Silicone oil 3 parts The coated film was cut to a width of 8 mm with a slitter and wound on a reel to prepare a thermal transfer ribbon. However, slitting was performed under two conditions, and a sample was prepared by cutting at a speed of 50 m / min under condition A and at a speed of 150 m / min under condition B.

Next, a 10-wire / mm energizing head was applied to plain paper at a voltage of 20 V.
When the characters were printed, clear prints were obtained. Also, none of the ribbons prepared under slit conditions A and B were cut during transfer recording. In addition, coating on the film, the film breaks even when slitting,
Wrinkling did not occur and the workability was good.

Example 2 Al was deposited on the aromatic polyamide film obtained in Example 1 to a thickness of 1000Å, and the ink layer was coated and slit (conditions A and B) as in Example 1 to prepare a thermal transfer ribbon. When a printing test similar to that of Example 1 was performed using this, a clearer print than that of Example 1 was obtained. In addition, no troubles such as wrinkles and cuts of the film occurred during the ribbon making and the transfer recording.

Example 3,4 75 mol% of 2-chloro-P-phenylenediamine and 4,4
25 mol% of 4'-diaminodiphenyl ether as a diamine component, 100 mol% of 2-chloroterephthalic acid chloride
Was polymerized in NMP using as an acid component, and further neutralized with lithium carbonate to obtain a polymer solution. The intrinsic viscosity is 2.
It was 6.

Carbon black was added to this polymer solution so as to have the concentrations described in Examples 3 and 4 in Table 1 to prepare two types of solutions, and films were formed from each in the same manner as in Example 1. . However, the stretching ratio is 1.2 times for MD and 1.1 times for TD. Table 1 shows the characteristic values of the obtained film.

The same method as in Example 2 is applied to each of these two types of films.
Al deposition, ink layer coating, slit (Condition A,
B) and a print test was performed. In each case, clear printing was obtained, and troubles such as wrinkles and cuts of the film did not occur during the preparation and transfer recording of the thermal transfer ribbon.

Example 5 Polymerization was carried out in NMP using 40 mol% of paraphenylenediamine, 60 mol% of 3,4'-diaminodiphenyl ether as a diamine component and 100 mol% of terephthalic acid chloride as an acid component, and neutralized with calcium carbonate. Intrinsic viscosity of
A 3.0 polymer solution was obtained.

Carbon black was added to this polymer solution, and a film was formed in the same manner as in Example 1. However, the draw ratio is
MD is 1.3 times and TD is 1.1 times. Table 1 shows the characteristic values of the obtained film.

Next, a thermal transfer ribbon was prepared in the same manner as in Example 2, and a printing test was performed. As a result, extremely clear printing was obtained. No trouble occurred.

Comparative Examples 1 and 2 Using the carbon black-added polymer solution of Example 1, films were formed in the same manner as in Example 1. However, in Comparative Example 1, the MD was 1.0 times and TD was 1.0 times, and in Comparative Example 2, the MD was 1.5 times and the TD was 1.0 times. Table 1 shows the characteristic values of the obtained film.

When a thermal transfer ribbon was prepared and printed using the same method as in Example 1 for each of the two types of films,
In Comparative Example 1 in which the mechanical properties were balanced by MD and TD, the thermal transfer ribbon created under slit condition A did not break during printing, but 100,000 characters were printed under condition B with increased slit speed. During this time, the ribbon was cut three times.

On the other hand, in Comparative Example 2 in which the Young's modulus of the MD was very large, the ribbon was cut during the printing test under both the slit conditions A and B, and the printing was uneven and the printing was not clear.

Comparative Example 3 A film was formed in the same manner as in Example 1 using the carbon black-added polymer solution of Example 4. However, the stretching ratio is MD1.55 times and TD1.0 times. Table 1 shows the characteristic values of the obtained film.

Next, a thermal transfer ribbon was prepared in the same manner as in Example 2,
When a printing test was performed, the ribbon was cut during printing, and the printing was unclear. This is considered to be because the film thermally contracted upon contact with the current-carrying head and fine wrinkles were formed on the ribbon.

Comparative Examples 4 and 5 Carbon black was added to the polymer solution of Example 5 so as to have the amount shown in Table 1, and a film was formed in the same manner as in Example 1. However, the MD in Comparative Example 4 was 1.
5 times, TD is 1.1 times, and in Comparative Example 5, MD is 1.3 times and TD is 1.2 times. Table 1 shows the characteristic values of the obtained film.

When a thermal transfer ribbon was prepared and printed using the same method as in Example 2 for each of the two types of films,
In Comparative Example 4 having a small Young's modulus of TD, the sample prepared by slitting under the condition B caused ribbon breakage during printing, and the printing was blurred and blurred regardless of the slit conditions.

On the other hand, in Comparative Example 5 in which the MD F5 value was small, the thermal transfer ribbon slit prepared under the condition B broke four times during printing, and the ribbon after printing appeared to be fully extended, and the printing was unclear. .

Claims (1)

(57) [Claims] 1. A thermal recording transfer body comprising an aromatic polyamide film containing carbon black in an amount of 10 to 40 (wt%) and an ink layer provided on one surface thereof, and a Young's modulus (Ym) in the longitudinal direction of the aromatic polyamide film. , Young's modulus in the width direction (Y
t) satisfies the formulas (1) and (2), Yt ≧ 400 (kg / mm ² ) (1) 1.05 ≦ Ym / Yt ≦ 2.00 (2) The F5 value in the longitudinal direction is 10 (Kg / mm ² ) As described above, the thermal recording transfer body is characterized in that the heat shrinkage stress in the longitudinal direction is 2.0 (Kg / mm ² ) or less at 100 to 250 ° C.