JPS61123589A - Heat transfer recording sheet and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain subject sheet with which transfer recording density can be continuously controlled by mixing an auxiliary material which has a melting point lower than the binder contained in an ink material and a certain solvent with the ink material which is provided with transferability by rise in temperature; and by being applied on a surface of a heat resistant substrate and the solvent is removed thereafter. CONSTITUTION:An ink material 120 which reduces viscosity by temperature rise recording control and gives transferability to a recording medium, and auxiliary particles 123 that are made from hot melt material which has a melting point (softening point) or a flow point lower than that of the binder 121 which constitutes the ink material, and does not thoroughly dissolve in the binder 121 at a normal temperature, and which is solid at the temperature are mixed with the solvent which can dissolve the binder 121 but can not thoroughly dissolve the auxiliary particles 123 at a normal temperature. The above mixture is applied in a fixed thickness to one surface of a heat resistant substrate 110, and then, the solvent is vaporized. Thus, subject recording sheet 100 which is made of a layer of the ink material 120 with the thickness which is less than at least some of the diameter of the auxiliary particles 123 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is useful for recording single-color gradation images, full-color images, etc. on a recording medium in continuous thermal gradation in one transfer using a thermal recording head, laser light, etc. The present invention relates to a thermal transfer recording sheet and a method for manufacturing the same.

2. Description of the Related Art Conventional thermal transfer recording sheet binding: 20 wt. Ester wax 40% by weight, mineral oil 10% by weight, other auxiliaries 10%
A thermal transfer layer with a thickness of about 4 μm consisting of an ink material layer in which 20% by weight of a pigment coloring material is mixed with an inder material is formed using a hot melt material consisting of 20% by weight.
A thermal transfer recording sheet formed by a hot melt coating method and having a melt transfer temperature of about 60°C is known (for example, Y, Tokunaga and K, Sugtyama).
.

”Therwal Ink-Transfer Image
ing”, IEEE Trans, on Electr.
on Devices, Vol, gD-2 Otsu PP,
218-222, 1980. ) Thermal transfer using this type of thermal transfer recording sheet is generally carried out by pressing a known thermal recording head against the back surface of the base sheet with the thermal transfer recording sheet in pressure contact with a recording medium such as recording paper, and applying the thermal transfer layer. Temperature recording is selectively controlled by a thermal recording head through the base sheet, and the ink material is melted and transferred to the recording medium.

Problems to be Solved by the Invention In such conventional thermal transfer recording sheets, the ink material layer extends from the base sheet side to the surface of the ink material layer, and the ink material does not adhere to the recording medium until the binder material has completely melted. , transcribed. In this case, since the ink material melted in the thickness direction of the ink material layer is attached and transferred to the recording medium at once, it is useful for binary density recording such as characters and figures, but it is useful for recording images with halftones, etc. Digital gradation methods, such as dithering and density pattern methods, are being considered for use in applications requiring continuous gradation.

However, with this type of digital gradation method, not only is the equipment expensive as it requires complex recording signal processing, but high image quality can be expected; It was inevitable that there would also be a significant decline.

The present invention has been made in view of these points, and an object of the present invention is to provide a thermal transfer recording sheet that can continuously control the transfer recording density in response to temperature-rising recording control, and a method for manufacturing the same.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an ink material for thermal transfer recording sheets whose viscosity is controlled to decrease through temperature-raising recording control, thereby imparting transferability to a recording medium. and has a lower melting point (softening point) or pour point than the binder material that is a constituent of the ink material,
A thermal transfer layer in which auxiliary particles made of a hot melt material that is not completely compatible with the binder material at room temperature and is solid at room temperature is mixed and dispersed in the ink material is placed on one side of a sheet-like heat-resistant substrate. and configure it.

Further, in the thermal transfer recording sheet, a mixed material containing a solvent material that dissolves the binder material but does not at least completely dissolve the auxiliary particles at room temperature, the ink material and the auxiliary particles is applied to one side of the heat-resistant substrate. After coating the surface of the ink material to a predetermined thickness, the solvent material is evaporated and removed, and the thickness of the layer made of the ink material is adjusted to the particle size of at least some of the auxiliary particles. It is manufactured by a solvent coating method characterized by the following constitution.

They may be colored or non-colored. In normal color transfer recording, the ink material includes a binder material and a coloring material made of pigments, dyes, or mixtures thereof used in conventional printing inks and paints, for example.

Furthermore, the term binder material collectively refers to materials whose viscosity decreases when the temperature rises and imparts transferability to recording media, and these materials are not limited to a single material but can be composed of multiple types of materials. , plasticizers, softeners, surfactants, chirotroping agents, and other auxiliary agents added as necessary are also included in the binder material.

Further, although the particle size of the auxiliary particles is preferably spherical, the particle size may not matter. Further, the particle size of the auxiliary particles may be the same particle size, or may have an appropriate particle size distribution from a small particle size to a large particle size.

The auxiliary particles are preferably non-colored, white, or transparent materials, but colored or opaque materials can be used as required. The auxiliary particles are also preferably compatible or partially compatible with the binder material when melted, but may be incompatible.

Function: In the present invention, the auxiliary particles are first melted by temperature raising recording control using a thermal recording head or the like via a heat-resistant substrate, and the binder located around the auxiliary particles is melted by heat conduction through the melted auxiliary particles. The material is melted. Therefore, when temperature raising recording is controlled by pulse width modulation with the recording medium in pressure contact with the surface of the thermal transfer layer, the melted auxiliary particles first permeate into the recording medium and are adhesively transferred in accordance with the pulse width. This penetration.

Along with the adhesive transfer, the ink material that is melted in the bath adjacent to the auxiliary particles and has a substantially lower viscosity together with the binder material penetrates into the recording medium and is adhesively transferred. Also, the auxiliary particles and the binder material are partially compatible. When the auxiliary particles and the binder material are selected for compatibility, the auxiliary particles and the binder material first become compatible and have a low viscosity along the surface of the auxiliary particles in accordance with the pulse width. Penetration of the auxiliary particulate material and the substantially reduced viscosity ink material containing the binder material compatible therewith into the recording medium through the contact interface of the materials.

Adhesive transfer.

The aforementioned substantial ink material penetration into the recording medium, adhesive transfer, increases with the thermal energy and thus pulse width of the rising 41-temperature recording control.

Wr<, after the pulse width modulation recording signal is applied to the thermal recording head etc., before the above-mentioned auxiliary particles and the ink material whose viscosity has been substantially reduced return to the original solid state, and before the recording medium is When the thermal transfer sheet and the recording medium are separated from each other in a low viscosity state that allows adhesive transfer, a transfer recording such as a monochrome image having continuous tone characteristics can be obtained in response to a pulse width modulation recording signal. In this case, by adding cyan, magenta, yellow, and il to the thermal transfer recording sheet, it is possible to record a full-color image by sequentially recording directly using a pulse width modulated primary color recording signal using the Nokyo color method or the four primary color method.

In this type of thermal transfer sheet, the viscosity diameter φ of at least some of the auxiliary particles is adjusted to the thickness t of the ink material layer (auxiliary particles The thickness of the ink material layer in the area where it is not located) is chosen to be less than the above-mentioned melting auxiliary particles,
Furthermore, there is an advantage that the ink material having a lower viscosity can be effectively penetrated into the recording medium and adhesively transferred.

The thermal transfer layer having such protruding auxiliary particles can be formed by using the unlevet coating method as described above, by appropriately selecting the mixed amount of the solvent material, applying the mixed material to the surface of the heat-resistant substrate, and after layering. By evaporating and removing the solvent material, the thickness of the ink material layer can be easily reduced to less than the particle size of at least some of the auxiliary particles.

Embodiment FIG. 1 is a partial cross-sectional structural diagram of an embodiment of thermal transfer recording sorting according to the present invention.

In the figure, 100 is a thermal transfer recording sheet, 100 is a sheet-like heat-resistant substrate, and 120 is a binder material 121 made of a hot melt material mixed with a coloring material 122 made of pigments, dyes, or both of these, and the thickness is t. This layer is made of ink material.

The thermal transfer layer 130 is formed by mixing and dispersing auxiliary particles 123 which are solid at temperatures ranging from 0'C to 36[deg.] C. and are not completely compatible with the binder material 121. In this embodiment, the particle diameter φ of the auxiliary particles 123 is selected to be smaller than the thickness t of the ink material layer 120, and the particles 123 cross the thickness direction of the layer 120, and a part of the particles may protrude from the surface 120a of the ink material layer. Note that the auxiliary particles 123 do not necessarily need to be in complete contact with the base surface 110a.

Furthermore, the protruding surfaces 123b of the auxiliary particles 123 may be thinly coated with the binder material 121 or even the coloring material 122.

For example, the heat-resistant base 110 has a thickness of 4 to 10 μm.
Polyethylene terephthalate (PET), polyimide film, or content paper is used.

For example, the binder material 121 and the auxiliary particles 123 are solid at least normally (0° C. to 35° C.), and the material 121
Among the particles 123, at least the material 121 is made of a single or multiple types of hot-melt material whose viscosity is reduced by temperature raising recording control and imparts adhesion and transfer adhesion to the recording medium (image receptor). If the temperature is less than 50°C, the ink material 120 and auxiliary particles 123 transferred and recorded on the recording medium
is susceptible to softening and set-off during storage, while 170
If the temperature exceeds 100 °C, it becomes difficult to control temperature-raising recording using a thermal recording head or the like.

Examples of hot melt materials include carte wax, beeswax, solid paraffin, non-aqueous solvent-soluble waxes such as microcrystalline wax, low molecular weight polyethylene, polyvinyl stearate, petroleum resin, polyamide resin, rosin modified resin, etc. Water-soluble hot melt materials such as non-aqueous solvent-soluble resins, polyethylene glycol, hydroxyethyl cellulose, polyacrylamide, and polyvinylpyrrolidone are used. These hot melt materials can be used alone or in combination as needed.

To make these hot melt materials flexible,
For example, softeners such as polyvinyl acetate, cellulose esters, acrylic resins, stearic acid, and lanolin can be added as appropriate.

When the hot melt material itself is highly flexible, for example, petroleum resin, low molecular weight polyethylene, etc., a softener may not be added. On the other hand, as the temperature rises, the viscosity decreases and the stickiness increases.
and an adhesive material that is fluid at room temperature (for example, 25°C), such as polybutine.

By adding polyimbutylene, polybutadiene, silicone oil, etc. to the hot melt material, it is possible to reduce the viscosity against elevated temperatures and to improve the overall transfer efficiency.

Binder material 121. The auxiliary particles 123 are appropriately selected from, for example, the above-mentioned hot melt materials.

In this case, the auxiliary particles 123 have a melting point (softening point) or pour point lower than that of the binder material 121, are not completely compatible with the material 121 at room temperature (for example, 0''C to 36°C), and are solid at room temperature. The materials are selected so that they are mixed and dispersed in the material 121 in the form of particles at room temperature.The effective selection is that when the binder material 121 is the non-aqueous solvent soluble hot melt material, the auxiliary particles 123 The above-mentioned water-soluble hot melt material is selected, or vice versa.When both the binder material 121 and the auxiliary particles 123 are selected to be non-aqueous solvent soluble, it is effective to configure the auxiliary particles 123 with carnauba wax, for example. be.

As the coloring material 122 in colored transfer recording, organic or inorganic pigments, water-soluble dyes or oil-bath dyes, or mixtures of multiple types of these coloring materials, which are used in commonly used printing inks and paints, can be suitably used. selected.

For example, the pigment for black transfer recording is carbon black, diamond plaque, and the dye is CI 5o.
lvent Black 3 or the like is used.

For full-color transfer recording, in addition to the above black color, CI Pigment Blue 15 (pigment) is used for cyan color.

CI 5olvent Blue 25 (dye), CI Pigment Red 57 (for magenta color)
(pigment), (J 5olventRed 49 (dye), CI PigmentYellow for yellow color
12 (pigment), CI Pigment Yellow
ow 1a (pigment), CI 5olvent Ye
Low 16 etc., pigment.

Thermal transfer 1i 130 is made using ink materials 120 of three primary colors of dyes or mixtures thereof or four primary colors including black.
are arranged on the same base sheet 110 in frame order, and these are superimposed and transferred to a recording medium such as recording paper in frame order, but the primary color thermal transfer layer is formed into a separate transfer sheet 1QO for each primary color. A known IJ near thermal recording head is arranged for each primary color transfer sheet, and pulse width modulated primary color recording signals of 3 to 4 primary colors are delayed in accordance with the position of each recording head, and are recorded line sequentially. Full-color recording is possible by overlapping transfers.

The mixed weight ratio of the binder material 121 and the coloring material 122 is, for example, 2 to 60% of the coloring material 122, so that the binder material 121
98-40% of people choose it.

When the coloring material 122 is a dye, if the mixed weight % is less than 2%, the transfer recording density is insufficient, and when the coloring material 122 is a pigment, and the coloring material exceeds 6Q%, the viscosity of the ink material 120 as a whole decreases. is insufficient, making it difficult to transfer and record onto a recording medium.

In particular, an ink material 120 in which the coloring material 122 is 10 to 60% and the binder material 121 is 9Q to 50% is recommended because it has excellent transfer recording density and continuous gradation. This range uses color materials with weather resistance in mind.

This is particularly useful when using pigments as 122.

Note that the ink material layer 120 can also be configured to be porous. In particular, when the coloring material 122 made of pigment is used, forming the ink material layer 120 by the norpent coating method makes it easy to control the evaporation of the true solvent contained in the solvent for the binder material 121, as well as the highly advantageous non-solvent added in a small amount. Can be made porous.

Although the auxiliary particles 123 are spherical in the figure, they do not necessarily have to be spherical and may be polygonal. Also, particle size φ
Although the same particles are shown, they may have any suitable particle size distribution. In this case, it does not necessarily matter if the particle size φ is smaller than the thickness t of the layer 130 and has a particle size distribution that partially includes particle sizes that can be buried in the layer 130. In this case, the particle size φ of particle 123 is expressed as an average pore size of 4 m◇
Particles 123 that are effective for continuous tone transfer recording are particles that satisfy φ〉t, and when φ〉t, they often exhibit the same behavior as the binder material 121, and this tendency is
The smaller the value, the larger the value.

The particle diameter φ of the auxiliary particles 123 is practically selected based on the correlation with the thickness t of the ink material layer 120. The grain size φ is the radius i
If n' is less than 1-6tl'nZ, the thickness t of the ink material layer 120 will be too small due to the requirement of t, and the transfer recording density to the recording medium (image receptor) such as recording paper cannot be high.
In addition, in terms of manufacturing, it is difficult to form effective auxiliary particles 123 of φkt protruding toward the layer surface 12Oa side, making it difficult to perform good continuous tone transfer recording, and making binary transfer similar to conventional thermal transfer recording sheets. Easy to record.

On the other hand, if the particle size φ of the auxiliary particles 1230 exceeds 15 μm, the heat capacity of the particles 123 becomes excessive, making it difficult for the thermal recording head to ascend or melt them as expected, resulting in lower sensitivity and lower maximum transfer recording density. descend.

Therefore, the preferred range of average particle diameter φm is 1.5 μm to 16 μm.
If m is 0, especially if the average particle diameter φm is selected within the range of 2 μm to 10 μm, the continuous gradation property, recording sensitivity, etc. will be good and this is a recommended range.

The arrangement density of the auxiliary particles 123 that satisfies φ>t is selected in consideration of the transfer recording pixel density and thermal transfer recording characteristics.

The lowest arrangement density is when the number is placed on the single side for each transfer recording density.

Normally, when gradation recording is performed using a known linear type thermal recording head, the recording density, that is, the transfer recording pixel density d, is selected to be 4 dots/beat or more from the viewpoint of image quality. Therefore, the hiding rate (
The minimum value of S (area ratio of particles 123 to unit area of base surface 110a) is φ=φmin (=', 5μtn
), it is given by (πφ2fnlnd2)/4, and when expressed in chi, d=4tono) ' / ohm is 2.8X10
%.

On the other hand, the maximum value of S is π/4 when a plurality of auxiliary particles 123 with φ>t are most densely arranged on the substrate surface 110a without overlapping each other, and therefore is 78.5% O 8 is appropriately selected within the above range.

In the above, if the arrangement density of the auxiliary particles 123 is too low, the continuous gradation property is likely to be impaired, and the transferred recorded image becomes rough especially in the low density region. To prevent these, particle 1
The arrangement density of 23 is 16 pieces/, (256 pieces/-9φml,
= 1.5am, S is 4.5 x 10-2%)
It is desirable to select more than one.

The auxiliary particles 123 can be colored with dyes, pigments, etc., or colored material particles can be used as needed, but if the color is different from the coloring material 122, the color will change depending on the transfer recording density. Or, in the case of the same color, the transfer recording density may change discontinuously, which may cause problems depending on the application.

Therefore, in order to achieve good continuous gradation, it is necessary to
It is preferable to avoid a significantly colored material and preferably select a colorless, white, or transparent material so as not to significantly affect the color brightness of the coloring material 122.

In addition, if the auxiliary particles 123 are selected to have a lower fusion heat energy, a lower specific heat, and a higher thermal conductivity than the binder material 121, there is an advantage that higher sensitivity and continuous gradation can be improved. .

The thickness t of the ink material layer 120 is appropriately selected so as to satisfy t<φ. The coating amount of the thermal transfer layer 130 as a whole is 1 m based on transfer recording density, continuous gradation, recording sensitivity, etc.
It is desirable to choose within the range of 0.81 to 51 per centimeter.

FIG. 2 is a system configuration diagram of a thermal transfer recording apparatus using a thermal transfer recording sheet according to an embodiment of the present invention.

510 is a linear type thermal recording head, which has a temperature rising recording section 5.
11 has a resistive heating element of 4 dots/1III1, for example.
They are arranged at a density of 1. A recording medium 2oO and a thermal transfer recording sheet 100 having a thermal transfer #130 are inserted and pressed between the temperature rising recording section 611 and a metal or heat-resistant platen 610, and the platen 610 is rotated as shown by an arrow 611.
12,613. 621 and 622 are a recording medium roll and a winding roll, respectively, and 631 and 632 are a transfer body roll and a winding roll, respectively.

520 sends a heat generation control electric signal 500A pulse-width modulated in accordance with the input image signal 500B to each of the resistance heating elements of the recording head 510. This is a modulated power supply device that converts and supplies line sequentially in synchronization with 11612°613. The recording head 510 performs temperature increasing recording control on the thermal transfer layer 130A corresponding to the recording section 511 in a line-sequential manner via the base 110. In this example, a large number of auxiliary particles 123 are located within each recording pixel, and the electrical signal 50
The heat generation of the heating resistor element is controlled in accordance with the pulse width Pw of 0A. By this temperature increase recording control, the auxiliary particles 123
is the melting auxiliary particle 1 that melts and becomes less viscous in accordance with Pw.
23' is formed.

On the other hand, the binder material 121 having a higher melting point than the auxiliary particles 123 forming the ink material 120 also melts and has a lower viscosity from the base surface 110a side, although it progresses at a slower rate than the particles 123, so-called molten ink material 120' having a lower viscosity. form.

It goes without saying that the thermal energy added during the filtration and melting of solid materials is dissipated as heat of fusion - its temperature is fixed at the melting point. However, the temperature of the molten material starts to rise again in a continuous manner in response to the applied thermal energy according to its specific heat and thermal conductivity. In this way, the unmelted binder material 121 in the ink material 120 in contact with the interface 123a' of the auxiliary melting particles 123' is supplied with heat of fusion by heat conduction via the auxiliary particles 123'.

Therefore, a so-called molten ink material 120' having a lower viscosity is generated along the particle interface 123a', and the range of the melting and lowering of the viscosity changes as the pulse width Pw increases.
spread around the area.

In this way, in a state where the recording medium surface 200a is configured to have ink affinity, the melting assisting particles 123' are attached to the surface 200a.
The molten ink material 120' is also permeated and adhered, and the molten ink material 120' is also drawn back and adhered at the same time.

Therefore, after the signal 500A is applied and before the melting auxiliary particles 123' and the melted ink material 120' return to their original solid state, the paper feed margins 12, 6
When the transfer sheet 100 and the recording medium 200 are peeled off at step 13, the ink material 120 melted in accordance with the pulse width Pw is attached to the recording medium 200 together with the auxiliary particles 123, and a transferred recording 160 is obtained.

The amount of melted ink material 120' increases with increasing pulse width Pw of signal 500A. Therefore, colorant 1 transferred to recording medium 200 along with melted binder material 121
22, that is, the optical density of the transfer record 160 increases continuously corresponding to Pw, and the transfer record 160 has a continuous gradation property.
0 is obtained. In this case, the maximum density of the transfer record 160 corresponds to the case where melting/melting has progressed to the entire surface of the ink material layer surface 120a.

In the above, the auxiliary particles 123 and the binder material 1
If 21 and 21 are selected to be partially compatible or completely compatible when the temperature is increased, there is an advantage that the transcription fi160 can be performed more effectively.

In these cases, care must be taken when peeling off the transfer sheet 100 and the recording medium 200, as this will affect the quality of the recorded and transferred image.

A good transferred image is obtained when the molten ink material 120' and the auxiliary melt particles 123' cool down after the recording signal pulse 500A is applied, and before they return to their original solid form, they retain fluidity to a certain extent and the particles 123' provides a means for quickly peeling off the recording medium 200 and the thermal transfer recording sheet 100 while maintaining transferability to the medium surface 200a, and this peeling is performed to prevent uneven peeling of the recorded image. This is always done after traveling a certain distance (for a certain period of time) from section 611.

In this example, the tension of the paper feeds 612 and 613 is increased and the recording unit 5
11, the sheet 1oO and the medium 200 are uniformly separated by, for example, a stripper 70o, so that the above conditions are satisfied.

The recording medium 200 may be uncoated paper or coated paper.

Synthetic paper such as polypropylene material, plastic film such as PET, cellophane, etc. are used.

The tsa diagram is a cross-sectional structure of another embodiment of the thermal transfer recording sheet according to the present invention. In this example, a case where the particle diameter φ of the auxiliary particles 123 has a distribution is shown. The auxiliary particles 123 embedded in the ink material 1ii 120 exhibit mainly the same behavior as the binder material 121.

The auxiliary particles 123 having a relationship of φ>t dominantly contribute to continuous tone transfer recording. In this case, the smaller φ is, the more the signal 6
Melting is completed at a narrow pulse width Pw of 00A, and a transfer record 160 is generated, and as φ increases, the heat capacity increases, so a wide pulse width Pw is required.

Therefore, the auxiliary particle 123 having the relationship φ>t in this way
By giving an appropriate distribution to the particle size of the pulse width Pv
This method has the advantage that the slope of the v vs. transfer recording density characteristic curve is gentle, and a good halftone image can be obtained.

Note that the adhesive strength of the base surface 110a of the thermal transfer layer 130 may sometimes be insufficient. For this improvement, the base surface 1
It can be improved by providing a thin (for example, about 1 μm) heat-resistant intermediate layer 124 of ethyl cellulose or polyvinyl butyral resin on the layer 10a, and placing a thermal transfer layer 130 thereon. Further, when the temperature increase recording control is performed by a light beam such as a laser beam, a photothermal conversion material such as carbon black may be mixed into the intermediate layer and used as a photothermal conversion layer.

In addition, when performing temperature increase recording control with a thermal recording head,
In order to prevent the back surface 110b of the base from melting and causing a stick phenomenon, or to ensure smooth running, a heat-resistant lubricant layer 111, such as polysal 7-on resin mixed with fine silica powder, is applied to a thickness of about 1 μm, for example. FIG. 4 is a cross-sectional structural diagram of still another embodiment of the thermal transfer recording sheet according to the present invention. Dispersing second auxiliary particles 124 having a melting point (softening point) or pour point higher than that of 121 in the ink material layer 120 together with first auxiliary particles 123 having a pour point;
Deploy.

Similar to the particles 123, the auxiliary particles 124 are also included in the ink material layer 1.
At least some of the particles are set to have a particle size larger than the thickness t of 20, and the preferable particle size range is also within the above-mentioned auxiliary particle 1.
23 shall be applied accordingly.

The second auxiliary particles 124 are, for example, alumina.

An inorganic powder such as glass, quartz, titanium oxide, or silica, or an organic resin powder such as epoxy resin or phenol resin is used, and the average particle size thereof is preferably selected to be approximately the same as that of the first auxiliary particles 123.

The above-mentioned concealment ms is selected within the above-mentioned range as a total value with the first auxiliary particle 123, preferably the first auxiliary particle 123
It is desirable to select the S[ of the second auxiliary particles 124 to be about the same level or lower than the S value of the second auxiliary particles 124.

According to the configuration shown in FIG. 1, the pulse width P of the signal 500A
When w increases beyond a certain level, melting reaches from the substrate surface 110a side to the ink material layer surface 120a, the entire layer 130 is transferred to the recording medium 200 at once, and the gradation in the high transfer recording density region is improved. may be lost.

In such a case, the second auxiliary particles 124 have the role of a spacer and have the role of preventing excessive pressure contact between the ink material layer surface 120a and the recording medium surface 200a, thus preventing the above-mentioned excessive transfer recording. This has the advantage that gradation in the high transfer recording density area is improved.

In the thermal transfer recording sheet according to the present invention, the auxiliary particles 123 must be partially embedded in the ink material layer 120 so that at least some of the particles satisfy φ>t.

A method for manufacturing a useful sheet 10o that satisfies this condition is as follows:
A mixed material containing a solvent material that dissolves the binder material 121 at room temperature but does not completely dissolve the auxiliary particles 123 at room temperature, and the ink material 120 and the auxiliary particles 123;
After coating and layering to a predetermined thickness on one surface side of the heat-resistant substrate 110, the thickness of the ink material layer 120 is reduced by evaporating and removing the solvent material. The diameter of at least some of the auxiliary particles 123 is smaller than that of the particles. In addition, in FIG. 1 and the like, a pigment or the like is used as the coloring material 122, and the ink material layer 120 is configured to be porous so as to have fine through holes that open on the ink material layer surface 120a side and penetrate to the base surface 110a side. You can also.

A configuration example will be described below.

[Example 1] As the binder material 121, an aromatic petroleum resin with a softening point of 120°C (Nippon Petrochemical Co., Ltd., Nisseki Neopolymer NP) was used as the binder material 121.
-120) 4.95 parts by weight, '77 as colorant 122
7 color pigment (CI Pigment Blue 15) 1
．． 8 parts by weight constitute the ink material 120, and 1.6 parts by weight of powder particles of carnauba wax, which also has a low melting point such as a petroleum resin and has a melting point of 83° C. and an average particle size of 6 μm, which covers the binder material 12, are added at room temperature. (2I5'C), xylene was selected as a solvent that dissolves petroleum resin but does not dissolve carnauba wax, and the mixed material to which 24 parts by weight of xylene was added was mixed at room temperature. A commercially available bar coater #
#6, made of PET film with a thickness of 9 μm,
Sheet-like base 110 having a heat-resistant lubricant layer 111 on the back surface
A layer is formed on top at room temperature, and the xylene is evaporated and removed.

The coated amount of the obtained thermal transfer layer 130 was 1.9ν, and carnauba particles as auxiliary particles 123 were dispersed and protruded on the surface of the thermal transfer layer 130, forming an uneven surface.

Using this thermal transfer recording sheet 1oO and a recording medium 2001 made of polypropylene synthetic paper with a thickness of 150 μm, transfer recording was performed using a thermal recording head 510.

The recording head 510 is a linear type with a recording density of 4 dos/mm, and the applied power per dot of the heating resistance element is 0.7
W, the main scanning recording speed is 16.7 ms/line, the sub-scanning recording density is 4 dots/mm, and the recording signal is pulse width modulated with 600 AFi 6 bits, and the maximum pulse width is 4 ms.

The optical density of the transfer record 160 is the pulse width PW=Q, 7
7 ml, the optical density rises smoothly from the paper surface optical density of the recording medium 200, and the highest transfer recording density is shown at Py = 3.3 mB. During this period, the recording density changes continuously with respect to Pw, showing good continuity. It showed gradation.

The coloring material 122 was changed to cyan pigment, and magenta (C
Engineering Pigmsnt Red-67) + Yellow color (CI
Pignent Yellow low 12), black (
Good continuous tone transfer recording characteristics were obtained even when using a pigment (carbon black).

[Example 2] According to the thermal transfer recording sheet 100 in which 1.5 parts by weight of alumina powder particles having an average particle size of 5 μm were added as second auxiliary particles 124 to the east and mixed and dispersed in Example 1, The optical density dependence of the transfer record 160 was gentler than that of Example 1, and the maximum transfer record density was obtained at Pw of 4 ms, and even better continuous tone characteristics were obtained.Example Similarly good continuous gradation characteristics were obtained with other pigment coloring materials.

Thus, the thermal transfer recording sheets according to Examples 1 and 2, 100
By using this method, it was possible to transfer and record not only single-color halftone images but also full-color images by overlapping the above-mentioned primary color sheets in a field-sequential manner.

Note that the following various methods are used to adjust the continuous tone characteristics. For example, a plurality of types of auxiliary particles 123 having different melting points (softening points) or pour points are mixed and used as the auxiliary particles 123. For example, in Example 1 and 2, the auxiliary particles 123
A mixture of carnauba wax (melting point: 83°C) and reseal wax (softening point: 108°C) powder particles is used. Furthermore, the mixing ratio is changed. The second auxiliary particles 124 may also be a mixture of a plurality of different material powders, or may be used with a different mixing ratio.

Furthermore, it is also effective to change the average particle size and further the particle size distribution of either or both of the first and second auxiliary particles 123 and 124.

The first auxiliary particles 123 may be material particles colored with dye or the like. In this case, continuous gradation will be slightly reduced, but
When the color material 122 is the same color, the optical density of the transfer record 160 is improved, and when it is a different color, the chromaticity of the transfer record 160 can be changed in accordance with the pulse width.

Effects of the Invention As described above, the present invention provides a thermal transfer recording sheet in which auxiliary particles having a low melting point (softening point) or pouring point are disposed in an ink material layer, and a method for manufacturing the same, which facilitates the desired thermal transfer. Not only can a recording sheet be manufactured, but by using this thermal transfer recording sheet, it is possible to perform continuous tone transfer recording using pigment coloring materials, which was difficult with conventional melt transfer recording sheets, and is suitable for OA, HA, new As a monochrome or full color printer for media, facsimile fields, etc., its industrial effects are extremely large.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional structural diagram of an embodiment of a thermal transfer recording sheet according to the present invention, and FIG. 2 is a system configuration diagram of a thermal transfer recording apparatus using an embodiment of a thermal transfer recording sheet according to the present invention.
FIG. 3 is a cross-sectional structural diagram of another embodiment of the thermal transfer recording sheet according to the present invention, and FIG. 4 is a cross-sectional structural diagram of still another embodiment of the thermal transfer recording sheet according to the present invention. Fig. 1 100---One heat transfer recording sheet tto---One twist resistance+! ! - Tortoise body tsuzo---Ink set 121---Baifugu 1 size/22-11-color 1 year old 13θ-111 transfer layer Figure 2 lπ-latent molten saccharide (l/,
/do 2) Figure 3 ff1---f d JP! ! , Appendix I Figure 4 Ken ff0 12+ Procedural amendment (method) % formula % Name of the invention Thermal transfer recording sheet and its manufacturing method 3 Relationship with the person making the amendment Patent application
Colonel Tokoro 1006 Oaza Kadoma, Kadoma City, Osaka Name (582) Matsushita Electric Industrial Co., Ltd. Representative Yama
Toshihiko Shimo 4 Agent 571 Address 1006 Taojimon Q, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 5 Date of amendment order, contents of amendment (1) Page 4, lines 3 to 3 of the specification Correct "(for example ~1980.)J in line 6 as follows. "(For example, Wai, Tokunaga and Kei, Sugyama, ′
Thermal Ink-Transfer Imaging', International Transactions on Electron Technologies. IED-27, pp. 218-222, 1980 (Y,
τokunaga and K+Sugiyama,
@ThermalInk-Transfer Ima
ging', r EKE Trtns+on
Electron Devices, vol, 1c
D-27. PP, 218-222.1980. )) J (2) Correct "C engineering to 16 etc." from page 14, line 17 to page 15, line 4 as follows. [CI Solvent Black 5 (OX301Y6
nt Black 3) etc. is used. In addition to the above, full color transfer recording is also possible. The cyan color is C.I. Pigment Blue 1s (
ax PigmantBlue15) (pigment). CI Solvent Blue 25 (CISolven
t Blue 25) (dye), C.I. Pigment Red 57 (CIPigment) for magenta color.
Red color) (pigment), C.I. Solvent
v-, do4 ca (CI 5olvent Rad4
9) (dye), C-I pigment for yellow color
Yeo-12 (CZ PigmentYeLLovv
12) (Pigment), C.I. Pigment Yeo
-17 (CI Pigment Yellow 1y
) (pigment), CI Solvent Yellow 1e (
CI 5olvent Yellow 1e) (
dyes) etc.”

Claims (4)

[Claims] (1) The viscosity is controlled to decrease by temperature increase recording control,
It has an ink material that imparts transferability to a recording medium, has a lower melting point (softening point) or pour point than a binder material that is a constituent of the ink material, and has a lower melting point (softening point) or pour point than the binder material that is a component of the ink material, and has A thermal transfer layer in which auxiliary particles made of a hot melt material that is not completely compatible with the material and is solid at room temperature are mixed and dispersed in the ink material in the form of particles,
A thermal transfer recording sheet characterized in that it is arranged on one side of a sheet-like heat-resistant substrate. (2) In the particle size distribution of the auxiliary particles, at least some of the particle sizes of the distributed particle sizes are set to be greater than or equal to the thickness of the layer made of the ink material. 1
) The thermal transfer recording sheet described in item 2. (3) has a melting point (softening point) or pour point higher than that of the binder material, is not completely compatible with the binder material at room temperature, and has at least a portion of the particle size distribution; The thermal transfer according to claim 2, characterized in that second auxiliary particles whose particle size is set to be larger than the thickness of the layer made of the ink material are further mixed and dispersed in the ink material. Record sheet. (4) The viscosity is controlled to decrease by temperature increase recording control,
It has an ink material that imparts transferability to a recording medium, has a lower melting point (softening point) or pour point than a binder material that is a constituent of the ink material, and has a lower melting point (softening point) or pour point than the binder material that is a component of the ink material, and has A thermal transfer layer in which auxiliary particles made of a hot melt material that is not completely compatible with the material and is solid at room temperature are mixed and dispersed in the ink material in the form of particles,
When manufacturing a thermal transfer recording sheet disposed on one side of a sheet-like heat-resistant substrate, a solvent material that dissolves the binder material but does not completely dissolve the auxiliary particles at room temperature, the ink material, and the auxiliary material are used. After layering a mixed material containing particles to a predetermined thickness on one surface side of the heat-resistant substrate, the solvent material is evaporated and removed, and the thickness of the layer made of the ink material is adjusted to A method for producing a thermal transfer recording sheet, characterized in that the particle size is smaller than that of at least some of the auxiliary particles.