JPH08310145A - Melt-transfer ink image receiving sheet and manufacture thereof - Google Patents

Abstract

PURPOSE: To transfer a melt-transfer ink image receiving sheet obtaining an image having high recording density, excellent gradation reproducibility, dot reproducibility and color clarity. CONSTITUTION: The melt-transfer ink image receiving sheet comprises a sheet- like support, and a porous ink acceptance layer formed on one surface of the support and of a porous resin containing liquid film, wherein the mean pore diameter of the surface of the acceptance layer is in a range of 0.5 to 30μm, and the optical contact ratio when the acceptance layer is pressurized by 2kg/cm<2> is in a range of 6 to 65%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melt transfer type ink image receiving sheet and a method for manufacturing the same. More specifically, when the present invention is used in a melt transfer type thermal transfer printer that uses a thermal head, the present invention is a melt transfer type ink receiving image that can obtain a print ink image having excellent gradation reproducibility and dot reproducibility together with recording density. The present invention relates to a sheet and a method for manufacturing the sheet.

[0002]

2. Description of the Related Art A thermal fusion transfer recording method using a thermal transfer ink sheet and a thermal head is widely used in printers such as word processors and facsimiles because of its simple mechanism and easy maintenance. High quality paper has been used as the melt transfer type ink image receiving sheet (image receiving sheet). However, in recent years, in order to obtain higher gradation reproducibility than before with the full-color thermal transfer recording, the size of each dot has been changed from the conventional method of obtaining gradation without changing the size of one dot in the printer. It is shifting to the dot variable method. On the image-receiving sheet, in full-color recording from low applied energy to high applied energy, the dot shape of the melt-transferred ink is faithfully reproduced. High is an important quality of recorded images.

With respect to the full-color thermal transfer image as described above, it is necessary to appropriately correspond the characteristics of the image receiving sheet. In other words, when non-coated paper for ordinary printing is used in the full-color hot-melt transfer method, a decrease in recording density, which is considered to be due to low heat insulation, and defective dot reproducibility due to insufficient cushioning may occur. There is. If the surface is too rough, ink will not be transferred, i.e., missing, or if the surface is too smooth, the anchoring effect of the ink will not work and the transferred ink will remain on the ink ribbon. Missing due to reverse transcription is likely to occur. All of these cause poor dot reproducibility. In addition to the decrease in the recording density due to the poor dot reproducibility as described above, the decrease in the recording density due to the low ink absorbability of the molten ink image receiving layer may occur.

As an attempt to solve these problems, it has been proposed to provide an undercoat layer containing hollow particles on a support in order to improve the cushioning property of the image receiving sheet (Japanese Patent Laid-Open No. 2-89690). Japanese Patent Laid-Open No. 64-64
27996). However, the cushioning property and heat insulating property of the image receiving sheet obtained by this method are still insufficient.
When the hollow particles are dissolved in the organic solvent of the image-receiving layer, an organic solvent-resistant polymer is used as an adhesive for the hollow particles, or a high organic solvent resistance is provided on the layer containing the hollow particles. It is necessary to provide a molecular layer, which is a manufacturing problem.

As another attempt to solve the above problem, on a sheet-shaped support containing plastic as a main component,
There is also an example in which a resin layer containing a component that dissolves in water is formed, and a water-soluble component is eluted and removed from the resin layer, thereby improving the ink receiving ability of the image receiving sheet (Japanese Patent Laid-Open No. HEI-2).
In this case, there is a defect that a sufficient maximum density cannot be obtained, or the printed image has no gloss, and it is not possible to satisfy the demanded quality that is increasing for the image receiving sheet. Further, since the image receiving sheet is mainly composed of plastic, it is difficult to recycle resources.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the drawbacks of the prior art, and has good dot reproducibility and gradation reproducibility even when used in a thermal transfer color printer, so that an ink image recording having a high recording density can be obtained. The present invention aims to provide a melt transfer type ink image receiving sheet.

[0007]

The melt transfer type ink image-receiving sheet of the present invention comprises a sheet-like support and a porous ink-receiving sheet formed on one surface of the sheet-like support and comprising a porous resin-containing film. The porous ink-receptive layer has an average pore diameter of 0.5 to 30 μm, and the porous ink-receptive layer has a surface area of 2 Kg / cm.
^The optical contact ratio when pressurized at ^{2 is} in the range of 6 to 65%.

The method for producing a melt transfer type ink image-receiving sheet of the present invention comprises a resin-containing liquid which is mechanically agitated to contain a large number of fine bubbles. The ratio of the volume of the foam to the volume before foaming) is more than 1 time and not more than 10 times, and coated on one surface of the sheet-shaped support and dried to form a porous ink-receiving layer, The average pore diameter of the surface of the porous ink receiving layer is 0.5.
To 30 μm, and when the porous ink receiving layer is pressurized at ² Kg / cm ² , the optical contact rate is controlled to be in the range of 6 to 65%. In addition, in the method for producing a melt transfer type ink image-receiving sheet of the present invention, the viscosity of the resin-containing liquid is preferably in the range of 5,000 to 100,000 cp when measured with a B-type rotational viscometer. .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive studies to achieve the above object, the present inventors have found that by forming a porous ink receiving layer containing a large number of fine bubbles on a sheet-like support, Further, it was found that the above problems can be solved by optimizing the average pore diameter of the surface of the porous ink receiving layer and the contact rate with respect to a plane optically measured under pressure, and thus the present invention is completed. I arrived.

That is, in recording with a melt thermal transfer printer, a resin containing liquid containing bubbles containing a large number of fine bubbles by mechanically stirring the liquid containing resin is
A porous ink-receiving layer is formed by coating and drying on a support, and the average pore diameter of the surface of the porous ink-receiving layer is in the range of 0.5 to 30 μm. Surface roughness under pressure, ie 2 Kg / c
Dot reproduction by controlling the optical contact ratio of the porous ink receiving layer with respect to one surface of the prism with light having a wavelength of 0.5 μm in the range of 6 to 65% while pressurizing with m ² , High gradation reproducibility and color vividness are achieved, and high density recording can be realized.

In the present invention, the porous ink-receiving layer contains a large number of fine air bubbles in a resin liquid or a liquid mixture containing a resin and a pigment as main components, which is coated on a sheet-like support and dried. However, there is no particular strict limitation on the method and equipment for forming and containing bubbles, and the coating method. Further, the bubble-containing state of the resin-containing liquid containing bubbles is not particularly limited, but the volume ratio of the bubble-containing liquid to the undiluted solution (hereinafter referred to as foaming ratio) is preferably more than 1 time and 10 times or less, It is preferably more than 1 time and 5 times or less. That is, the expansion ratio is a measure showing the bubble content in the resin solution containing bubbles, and means that the larger the expansion ratio is, the thinner the thickness of the resin film (wall) constituting the bubbles becomes. Further, when the expansion ratio is the same, it means that the lower the solid content concentration of the resin-containing mixed liquid before foaming is, the thinner the resin film is. As described above, when the resin film becomes thin, it may be difficult to maintain the strength of the resulting porous ink receiving layer at a sufficient level. In this respect, the balance between the expansion ratio and the resin-containing mixed liquid composition is Great care should be taken.

Further, the reason why the image-receiving sheet of the present invention exhibits excellent melt ink transfer recording performance is that the physical characteristics (structural characteristics, surface smoothness, etc.) of the porous ink-receiving layer are involved. Conceivable. From the viewpoint of structural characteristics, since there are many fine holes on the surface of the image receiving sheet, it has excellent absorbing ability of the melted ink by the capillary force (anchoring effect), so that it melts into the porous ink receiving layer. It is considered that the ink permeability is improved and a high ink receiving ability is exhibited.

In this respect, the size of the pores on the surface of the porous ink receiving layer formed on the image receiving sheet is important. That is, when the molten ink is transferred, in order to form a good image on the image receiving sheet of the present invention, the average pore diameter of the surface of the porous ink receiving layer needs to be in the range of 0.5 to 30 μm. Yes, preferably 0.5 to 2
It is in the range of 0 μm. The pore diameter is related to the ability to capture molten ink by capillarity due to its size, the smaller the pore, the greater the ability. On the other hand, if the size of the pores becomes too large, the transfer ink will be buried in the pores, or it will cause poor transfer or uneven transfer to prevent good contact between the ink ribbon and the surface of the porous ink-receiving layer, Dot reproduction failure occurs and a good image cannot be formed. The pore diameter of the surface of the porous ink receiving layer can be measured using an optical microscope or a scanning electron microscope photograph and an image analyzer.

The size of the pores depends on the composition of the resin-containing mixed solution before the bubble formation / dispersion treatment, that is, the type of material, the compounding ratio, and the solid content concentration, that is, foaming, coating, and drying after receiving the porous ink. The amount that remains as a component directly related to the film thickness in the layer, or the expansion ratio, the coating method, etc.
Since it is often affected by various factors, it is necessary to set appropriate conditions. Further, the size of the pores on the surface of the porous ink receiving layer in the present invention is also related to the size of the bubbles in the resin solution containing bubbles, which are obtained by mechanical stirring, and the bubbles in the liquid solution containing resin are generally small. Since the pores on the surface of the ink-receiving layer after coating and drying become smaller, there is no particular limitation on the bubble-containing state of the resin-containing mixed solution, but the same size as the surface of the porous ink-receiving layer, that is, , Preferably with an average diameter of 0.5 to 30 μ
It is preferable that the fine bubbles in the range of m are dispersed and mixed, and more preferably the average diameter is in the range of 0.5 to 20 μm. The size of the contained bubbles can be measured with an image analyzer by photographing a part of them with an optical microscope.

As another feature of the structural aspect, when observing the cross section of the porous ink receiving layer of the present invention with a scanning electron microscope or the like, many pores in the receiving layer are present in the resin-containing film surrounding the pores. And the adjacent pores communicate with each other (that is, continuous pores are formed). Therefore, since the porous ink receiving layer of the present invention has the above internal structure, the transferred molten ink penetrates into the pores on the surface of the receiving layer and is trapped inside the receiving layer. It exhibits a high ink receiving ability.

Further, as a physical property of the porous ink receiving layer, its surface roughness is also an important property. That is, in image formation by melt transfer, the surface of the porous ink receiving layer comes into contact with the surface of the heat melting type ink ribbon while being pressed by the platen roll from the back surface of the image receiving sheet. On the other hand, in many systems, heat is applied from the back surface of the ink ribbon by a thermal head to melt the ink on the ink ribbon and transfer it to the ink receiving layer. Therefore, the surface roughness of the porous ink receiving layer is a factor that has an important influence on the image quality in the adhesion to the ink ribbon.

As a general method for measuring the surface roughness of a sheet-like material, that is, the surface smoothness, the surface smoothness is expressed by the time required to flow a certain amount of air over the surface to be measured (surface smoothness). Is better, the more time it takes), for example there is an air leak type Oken smoothness meter. However, as described above, in the porous ink-receiving layer of the present invention, since the pores on the surface of the porous ink-receiving layer and the pores existing inside the layer are in communication with each other, the air supplied for the measurement is the receiving layer. The smoothness of the surface of the receiving layer cannot be evaluated correctly because it permeates not only the surface but also inside the layer. Further, as another method, there is a non-contact type surface roughness measuring device which irradiates and scans a laser beam on the surface to be measured, or a light beam using a general white light as a light source, and the like. Since the molten ink is transferred to the image-receiving sheet under pressure, such a method cannot evaluate the smoothness of the surface of the porous ink-receiving layer in a state close to that in actual use.

Therefore, it is necessary to evaluate the surface smoothness of the porous ink-receiving layer of the image-receiving sheet of the present invention under pressure. For example, a commercially available Microtopograph (trademark, manufactured by Toyo Seiki Seisakusho KK) Manufactured), and the optical contact rate is measured. Here, the optical contact ratio by the microtopography will be briefly described. Press the measured surface onto one surface of the prism,
When parallel light is incident at an angle of 45 degrees from the prism side, reflection occurs at the boundary surface of media having different refractive indexes. At this time, the light digs into the boundary surface, that is, the inside of the surface to be measured, and reflects according to the wavelength (the shorter the wavelength, the shallower the depth of digging into the light, so that the light is easily reflected in the vicinity of the surface). The microtopography utilizes such properties of light to measure the optical contact ratio (expressed as a percentage) between the prism and the measured surface under pressure from the ratio of the reflected light amount to the incident light amount. The larger the value of the optical contact rate, the better the surface smoothness of the surface to be measured under pressure.

The surface smoothness of the porous ink receiving layer under pressure has a high correlation with the expansion ratio of the bubble-containing resin liquid, as can be inferred from the method for producing the image receiving sheet of the present invention. That is, a porous ink receiving layer formed from a foam coating material having a high bubble content (paint having a high expansion ratio),
Since the resin film is thin, it tends to be softened, so that the surface smoothness (optical contact rate) under pressure also increases.

The porous ink-receiving layer of the image-receiving sheet of the present invention is 2 Kg / cm using the above microtopography.
The optical contact ratio is 6 to 65 when pressure is applied to one surface of the prism with a pressure of ² and measurement is performed using light having a wavelength of 0.5 μm.
It is important to control the content to be in the range of%, preferably 6 to 30%. That is,
When the optical contact ratio is 6% or less, the surface smoothness under pressure is not sufficient, so that good adhesion with the ink ribbon cannot be obtained. On the other hand, when the optical contact ratio exceeds 65%, the surface smoothness under pressure is improved and the adhesion with the ink ribbon is improved, while the resin film in the porous ink receiving layer becomes thin and the strength is sufficient. May not be maintained, so it is not suitable for practical use.

The porous ink receiving layer formed on the sheet-shaped support of the present invention contains a resin or a resin and a pigment as main components. Such a porous ink-receiving layer is a liquid material containing a resin or a mixture of a resin and a pigment, which is subjected to mechanical agitation to disperse and contain a large number of fine air bubbles therein, It can be formed by coating on a support.

The resin used for forming the porous ink receiving layer in the present invention includes, for example, polyvinyl alcohol and its derivatives having various molecular weights and saponification degrees.
Starch, its derivatives and various modified starches such as oxidized starch, cellulose derivatives such as methoxycellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylic acid amide-acrylic acid ester copolymer, acrylic Acid amide-acrylic acid ester-methacrylic acid ester copolymer, styrene-
Alkali salt of maleic anhydride copolymer, polyacrylamide and its derivatives, water-soluble resin such as polyethylene glycol, polyvinyl acetate, polyurethane, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polyacrylic ester , Vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, ethylene-vinyl acetate copolymer, styrene-butadiene-
Aqueous dispersion resins such as acrylic copolymers and latexes such as polyvinylidene chloride, and glue, casein, soybean protein, gelatin, sodium alginate and the like can be used, but are not limited thereto. These resins can be used alone or in combination of two or more, if necessary.

In the present invention, examples of pigments that can be contained in the porous ink receiving layer include zinc oxide, titanium oxide, calcium carbonate, silicic acid, silicates, clay, talc, mica, calcined clay, and hydroxide. Inorganic pigments such as aluminum, barium sulphate, lithopone and colloidal silica, spheres such as polystyrene, polyethylene, polypropylene, epoxy resin, styrene-acryl copolymer, hollow, or plastic pigments processed into various shapes. Organic pigments, starch powders, cellulose powders, etc. can be used, but are not limited thereto. In addition, these pigments can be used alone or in combination of two or more, if necessary. The compounding ratio of the above resin and pigment for obtaining a good melt heat transfer image is in the range of 0 to 900 parts by weight of the pigment with respect to 100 parts by weight of the solid content of the resin liquid. If the number of parts mixed with the pigment exceeds this range, the required porous coating film strength cannot be obtained, and a film peeling trouble occurs during image formation, and a good image is often not obtained.

In the resin before foam formation or in the mixture of the resin and the pigment, known viscosity modifiers (so-called thickeners, etc.), dispersants, dyes (dyes), water-proofing agents, and lubricants are added, if necessary. , A cross-linking agent, a plasticizer and the like can be added.

Onto the sheet-like support of the porous ink receiving layer
Coating amount is 1m on one side of the support ²Dry weight per
2 to 40 g (2 to 40 g / m²) Range
To 2g / m coating amount²Support if less
It can be difficult to adequately cover the surface roughness of the body
A lot of surface image receiving sheets with proper smoothness can be obtained.
May not be obtained or sufficient compression deformability may not be obtained.
It On the other hand, it is 40g / m²If it exceeds
The thickness of the porous ink receiving layer becomes too large,
When the image is formed, the bonding strength in the receptor layer decreases
The ink receiving layer of the
A good image may not be formed in some cases. Therefore, the porous
Appropriate amount of coating on the ink receiving layer
It is natural to pay sufficient attention to it as well as to change it.

The method for producing the porous ink-receiving layer of the present invention has a viscosity of 5 at 23 ° C. measured by a B-type viscometer of the resin-containing liquid before forming and dispersing bubbles by mechanical stirring. 1,000 to 100,000 cp
Is preferably in the range of 10,000 to 50,
A more preferable result is obtained in the range of 000 cp. When the viscosity of the resin-containing liquid is less than 5,000 cp,
The stability of the bubbles formed and dispersed by the mechanical stirring treatment deteriorates (broken bubbles and coalescence of bubbles easily occur), and it becomes difficult to hold fine bubbles. As a result, a preferable pore diameter on the surface of the porous ink receiving layer cannot be obtained, and the recording performance of the fusion type thermal transfer image receiving sheet is deteriorated. As the viscosity of the resin-containing liquid before mechanical stirring becomes higher, the size of the bubbles dispersed in the liquid becomes finer, but when it exceeds 100,000 cp, the stability of the bubbles is not a problem, Formation of the
Since the viscosity of the foamed resin-containing liquid further increases with dispersion as compared with that before the stirring treatment, the coatability on one surface of the support may be deteriorated, and problems such as uneven coating may occur. . Further, the energy consumed for the mechanical stirring process becomes excessive, which is disadvantageous from the economical and energy saving viewpoints. The method for controlling the viscosity of the resin-containing liquid is not particularly limited, and examples thereof include various molecular weights such as carboxymethyl cellulose and its derivatives, polyacrylic acid modified products, sodium alginate, and maleic anhydride copolymers. Known materials can be used as appropriate.

In the present invention, a method of containing and dispersing bubbles in a resin-containing liquid (hereinafter referred to as a foaming method) is, for example, a so-called confectionery foaming machine having a stirring blade that rotates while performing a planetary motion, and generally an emulsion dispersion. For example, homogenizers such as homomixers, cowless dissolvers, etc., or mechanically agitating while continuously feeding a mixture of air and resin-containing liquid into a closed system into air into fine bubbles. dispersion,
Devices that can be mixed, such as Gaston County, Inc.
A continuous foaming machine such as Stoke Co. of the Netherlands can be used, but there is no particular strict limitation.

Further, as an additive, the capacity of equipment for mechanical stirring is insufficient, so that the desired state of containing bubbles cannot be obtained, or the stability of bubbles in the resin liquid containing bubbles is improved. For this purpose, it is possible to appropriately select and blend from materials having a wide range of surface-active properties, which are called foam stabilizers and foaming agents. For example, higher fatty acids,
Higher fatty acid modified products, alkali salts of higher fatty acids, amine salts of higher fatty acids, etc. can be used because they have a particularly high effect of enhancing the foamability of the resin-containing liquid and a high effect of improving the stability of the dispersed and contained bubbles. . There is no particular strict limitation on the selection, but it is appropriate to avoid the use of a material that may significantly impede the fluidity of the resin-containing mixed solution or impair the coating workability. Further, the compounding ratio of the foam stabilizer or the foaming agent to the resin liquid or the mixed liquid of the resin liquid and the pigment is 100 parts by weight of the solid content of the resin liquid or the mixed liquid of the resin liquid and the pigment. For solid content of 0-3
The amount is 0 parts by weight, preferably 1 to 20 parts by weight, and even if the amount is more than 30 parts by weight, the intended effect cannot be largely improved in many cases.

As a coating method for forming the porous ink receiving layer on the support, a Meyer bar method, a gravure roll method, a roll method, a reverse roll method, a blade method, a knife method, an air knife method, an extrusion method. , A casting method, or any other known method. The sheet having the porous ink-receiving layer of the present invention can obtain a good melt heat transfer image even in a state where it is coated with the resin mixture containing a bubble-containing resin and dried, and further, two or more metal rolls are used. A machine calender composed of, or a super calender composed of a metal roll and a resin roll or a metal roll and a cotton roll, etc. is used in an appropriate manner, and the porous ink receiving layer is subjected to a finishing treatment. The smoothness of the surface can be further improved. After coating again,
The sheet in the semi-dried state or the dried state may be brought into contact with a heated or non-heated cast drum having a mirror finish to improve the surface of the porous ink receiving layer having the smooth surface. However, when the above smooth finish treatment is applied under excessive pressure, the resin wall surrounding the bubbles in the porous ink receiving layer is destroyed and the ink receiving layer is densified, resulting in deterioration of heat insulation and cushioning properties. Or, since the pores on the surface of the ink receiving layer are deformed or destroyed, the excellent molten ink transfer performance of the porous ink receiving layer may not be obtained. Therefore, it is necessary to thoroughly consider the processing conditions in the above smooth finish processing.

As the sheet-like support used in the present invention, paper having cellulose as a main component, coated paper, laminated paper and the like, and woven cloth, non-woven cloth and the like can be used. is there. Further, plastic films such as polyolefin, methacrylate and cellulose acetate, synthetic paper made of polyolefin and pigment, and porous synthetic resin film such as foamed polyethylene terephthalate film and foamed polypropylene film can be used.
The better the heat insulation of these supports, the better the dot reproducibility, gradation reproducibility and color vividness with the same applied energy, and the increase in recording density can be achieved. Also, since the amount of energy required to obtain recording quality is small, it is also effective in energy saving. In addition, when paper or coated paper containing pulp as a main component is used as a support, there is an advantage that it can be particularly recycled.

Further, when the air bubble-containing resin liquid is applied onto the above sheet-like support to produce the image-receiving sheet of the present invention,
In the steps of coating, drying and winding, the sheet itself may curl with its coated surface inside or outside. In this case, if the sheet is used after being cut into an image forming sheet having a predetermined size, the sheet may not be normally fed to the image forming apparatus, or the running property inside the apparatus may deteriorate. May cause trouble. Further, the melt transfer recording method is a method in which a heat source is brought into contact with an ink ribbon and the dye component in the ribbon is transferred onto a recording sheet, so that the porous ink receiving layer, which is the image forming surface, and the support layer are heated. Due to the difference in shrinkage or the difference in expansion characteristics that accompanies the image receiving sheet, curling occurs inside the apparatus, and the above-mentioned trouble occurs. Due to such curling, an image is formed obliquely with respect to the normal paper surface direction, and wrinkles are likely to occur on the sheet inside the apparatus, so that the ink ribbon and the image receiving sheet are not normally contacted and Poor transfer may occur, resulting in poor image quality.

In order to prevent various troubles caused by such curl, the difference in shrinkage property or the difference in expansion property between the porous ink receiving layer and the support layer due to heating should be minimized. Is desirable. Therefore, a curl prevention layer may be coated or laminated on the back surface of the sheet, that is, the surface opposite to the porous ink receiving layer. Material of this anti-curl layer, forming method, coating amount,
There are no restrictions on the amount of lamination etc., the type of support,
The thickness or the properties of the porous ink receiving layer, that is, the material composition, the expansion ratio, the coating amount, and other various factors can be taken into consideration for optimization.

Depending on the selection of the material of the support, when the image receiving sheet to be obtained runs in the image forming apparatus, various frictional forces may be exerted on the mechanism of the apparatus, and heating may cause a decrease in humidity inside the apparatus. The image receiving sheet may be charged with static electricity singly or in combination. When a large number of images are continuously formed in such a state, the image forming surface of the image receiving sheet and the back surface of the next image receiving sheet are electrostatically adhered to each other and are difficult to peel off. In particular, since various plastic sheets or synthetic papers are inherently prone to being charged with static electricity, when these are used as a support, static electricity is generated during the sheeting process by cutting or during storage after processing. Therefore, it becomes difficult to remove the front and back of the sheet. As a matter of course, even when paper is used as the support, the above troubles can occur. It is extremely effective to form a so-called antistatic layer on the back surface of the image receiving sheet in order to prevent such troubles due to charging. Charging can also be achieved by using an antistatic material, or by reducing the coefficient of friction between the sheet back surface and the porous ink receiving layer. Therefore, the antistatic layer can be formed by appropriately selecting from a wide range of materials and methods as in the formation of the curl preventing layer.

The anti-curl layer and the antistatic layer can be separately formed on the back surface of the support to obtain desired performance, but the production process is simplified, the production cost is reduced, or the intended performance is reduced. The purpose can be achieved by forming a single layer by appropriately selecting the material and the forming method as required, such as the functional level. Ie a single layer to prevent curl,
It is also possible to impart trouble prevention performance such as antistatic. Therefore, there is no limitation on the number of layers formed on the back surface of the sheet-shaped support.

[0035]

The present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited by these. In addition, "part" in Examples and Comparative Examples
Represents the number of parts by weight relative to the solid content of the resin.

Example 1 A resin mixture having a composition shown below (viscosity 20,000)
cp, solid content concentration 30%) was stirred for 10 minutes at a stirring speed of 490 rpm using a stirrer (trademark: Kenmix Aiko PRO, manufactured by Aikosha Co., Ltd.) to perform foaming treatment. The expansion ratio was 4.0 times. Resin mixture composition Aqueous polyurethane resin (trademark: ADEKA BON TITER HUX-401, manufactured by Asahi Denka Co., Ltd.) 100 parts Higher fatty acid amide foam stabilizer (trademark: YC80C, manufactured by Kanebo NSC Co., Ltd.) 5 parts Viscosity control (For thickening) Sodium carboxymethyl cellulose (trademark: AG gum, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 10 parts Immediately after foaming the above-mentioned bubble-containing resin mixed liquid, 75 g of tsubo
/ M ² on the surface of high-quality paper using an applicator bar so that the coating amount (dry matter amount) is 15 g / m ² ,
After drying, a porous ink receiving layer was formed to prepare an image receiving sheet.

Example 2 Using the applicator bar, the bubble-containing mixed solution of Example 1 was applied to a high-quality paper of 75 g / m ² in weight per square meter so that the coating amount (dry matter amount) was 25 g / m ^2. After coating and drying, a porous ink receiving layer was formed to prepare an image receiving sheet.

Example 3 A resin mixture having the same composition as in Example 1 was stirred with the same stirrer as in Example 1 at 490 rpm for 25 minutes to prepare a bubble-containing resin mixture having an expansion ratio of 9.0. . Immediately after the foaming treatment, the coating amount (dry matter amount) was 5 g / m ² on the surface of a high-quality paper of 75 g / m ² by using an applicator bar.
Was coated and dried to form a porous ink receiving layer, and an image receiving sheet was produced.

Example 4 A synthetic paper having a thickness of 110 μm (trademark: YUPO FPG110, manufactured by Oji Yuka Synthetic Paper Co., Ltd.)
The coating amount (dry matter amount) is 1 using the applicator bar.
It was coated at 5 g / m ² and dried to form a porous ink receiving layer to prepare an image receiving sheet.

Example 5 The resin mixture having the same composition as in Example 1 was stirred for 8 minutes by the same stirrer as in Example 1 to prepare a bubble-containing resin mixture having a foaming ratio of 2.0. Immediately after foaming treatment
On the surface of the high-quality paper of m ² is coated using an applicator bar so that the coating amount (dry matter amount) is 30 g / m ² ,
After drying, a porous ink receiving layer was formed to prepare an image receiving sheet.

Example 6 A resin mixture having the composition shown below (viscosity 20,000)
(cp, solid content concentration 40%) was subjected to foaming treatment in the same manner as in Example 1. The expansion ratio was 3.0 times. Resin mixture composition Aqueous polyurethane resin (Trademark: ADEKA BON TITER HUX-401, manufactured by Asahi Denka Co., Ltd.) 100 parts Kaolinite clay (Trademark: HT clay, manufactured by Engelhard) 100 parts Higher fatty acid alkaline salt type foam stabilizer Agent (Trademark: DC-100A, manufactured by San Nopco Ltd.) 10 parts Sodium carboxymethyl cellulose for viscosity adjustment (for thickening) (Trademark: AG gum, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 10 parts Bubble-containing resin mixture described above Immediately after foaming the liquid,
An image receiving sheet on which a porous ink receiving layer is formed by coating the surface of a high quality paper of g / m ^{2 with} an applicator bar so that the coating amount (dry matter amount) is 15 g / m ² and drying. Was produced.

Example 7 The image-receiving sheet of Example 6 was conditioned at 20 ° C. and a relative humidity of 65% for a whole day and night, and then, with a super calender, the optical contact ratio of the surface of the porous ink-receiving layer by the microtopography ( Pressure: 2Kg / cm ² , wavelength used: 0.5
(μm) was 23.0%. The optical contact ratio of the unprocessed supercalender sheet of Example 6 measured under the same conditions was 15.3%.

Example 8 A resin mixture having the following composition (viscosity 20,000 c
(p, solid content concentration 40%) was subjected to foaming treatment in the same manner as in Example 1. The expansion ratio was 3.0 times. Resin mixture composition Aqueous polyurethane resin (trademark: ADEKA BON TITER HUX-401, manufactured by Asahi Denka Co., Ltd.) 100 parts Kaolinite clay (trademark: HT clay, manufactured by Engelhard) 900 parts Higher fatty acid alkali salt type foaming Agent (Trademark: DC-100A, manufactured by San Nopco Ltd.) 30 parts Sodium carboxymethyl cellulose for viscosity adjustment (for thickening) (Trademark: AG gum, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 10 parts The above-mentioned bubble-containing resin mixture Immediately after foaming the liquid 75 g
/ M ² on the surface of high-quality paper using an applicator bar so that the coating amount (dry matter amount) is 15 g / m ² ,
After drying, a porous ink receiving layer was formed to prepare an image receiving sheet.

Example 9 A resin mixture having the composition shown below (viscosity 20,000)
(cp, solid content concentration 30%) was subjected to foaming treatment in the same manner as in Example 1. The expansion ratio was 4.0 times. Resin mixture liquid composition Aqueous polyurethane resin (trademark: ADEKA BON TITER HUX-401, manufactured by Asahi Denka Co., Ltd.) 50 parts SBR latex (trademark: L-1612, manufactured by Asahi Kasei Co., Ltd.) 50 parts Higher fatty acid amide-based preparation Foaming agent (Trademark: YC80C, manufactured by Kanebo NSC Co., Ltd.) 5 parts Sodium carboxymethyl cellulose for viscosity adjustment (for thickening) (Trademark: AG gum, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 10 parts The above-mentioned foam-containing resin mixture Immediately after foaming the liquid 75 g
/ M ² on the surface of high-quality paper using an applicator bar so that the coating amount (dry matter amount) is 15 g / m ² ,
After drying, a porous ink receiving layer was formed to prepare an image receiving sheet.

Example 10 A resin mixture having a composition shown below (viscosity 20,000)
cp, solid content concentration 25%) was subjected to foaming treatment in the same manner as in Example 1. The expansion ratio was 4.0 times. Resin mixture liquid composition Aqueous polyurethane resin (trademark: ADEKA BON TITER HUX-401, manufactured by Asahi Denka Kogyo Co., Ltd.) 50 parts Oxidized starch (trademark: Oji Ace A, manufactured by Oji Corn Starch Co., Ltd.) 50 parts Higher fatty acid amide type preparation Foaming agent (Trademark: YC80C, manufactured by Kanebo NSC Co., Ltd.) 5 parts Sodium carboxymethyl cellulose for viscosity adjustment (for thickening) (Trademark: AG gum, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 10 parts The above-mentioned foam-containing resin mixture Immediately after foaming the liquid 75 g
/ M ² on the surface of high-quality paper using an applicator bar so that the coating amount (dry matter amount) is 15 g / m ² ,
After drying, a porous ink receiving layer was formed to prepare an image receiving sheet.

Example 11 Resin mixture having the composition shown below (viscosity 20,000)
(cp, solid content concentration 30%) was subjected to foaming treatment in the same manner as in Example 1. The expansion ratio was 4.0 times. Resin mixture composition SBR latex (trademark: L-1612, manufactured by Asahi Kasei Kogyo Co., Ltd.) 100 parts Higher fatty acid amide foam stabilizer (trademark: YC80C, manufactured by Kanebo NSC Co., Ltd.) 5 parts For viscosity adjustment (for thickening) ) Sodium carboxymethyl cellulose (trademark: AG gum, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 10 parts Immediately after foaming the above-mentioned bubble-containing resin mixture, 75 g of tsubo
/ M ² on the surface of high-quality paper using an applicator bar so that the coating amount (dry matter amount) is 15 g / m ² ,
After drying, a porous ink receiving layer was formed to prepare an image receiving sheet.

Example 12 The resin mixture having the same composition as in Example 1 was stirred for 13 minutes with the same stirrer as in Example 1 to prepare a bubble-containing resin mixture having a foaming ratio of 5.0 times. 75 tsubo immediately after foaming
On a surface of a high-quality paper of g / m ² , using an applicator bar, a coating amount (dry matter amount) of 15 g / m ² was applied, followed by drying to form a porous ink-receiving layer, An image receiving sheet was produced.

Example 13 Resin mixture having a composition shown below (viscosity 6,000 c
p, solid content concentration 35%) was stirred for 6 minutes with the same stirrer as in Example 1 to prepare a bubble-containing resin mixed solution having a foaming ratio of 4.0. Immediately after the foaming treatment, it was coated on the surface of a high-quality paper of 75 g / m ² by using an applicator bar so that the coating amount (dry matter amount) was 15 g / m ² , dried, and then porous. An ink receiving layer was formed to prepare an image receiving sheet. Resin mixture composition Aqueous polyurethane resin (trademark: ADEKA BON TITER HUX-401, manufactured by Asahi Denka Co., Ltd.) 100 parts Higher fatty acid amide foam stabilizer (trademark: YC80C, manufactured by Kanebo NSC Co., Ltd.) 5 parts Viscosity control (Thickening) sodium carboxymethyl cellulose (trademark: AG gum, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 4 parts

Example 14 Resin mixture having a composition shown below (viscosity 50,000)
cp, solid content concentration 25%) was stirred with the same stirrer as in Example 1 for 12 minutes to prepare a bubble-containing resin mixed solution having a foaming ratio of 4.0. 75 g / m ²
On the surface of the high-quality paper using an applicator bar so that the coating amount (dry matter amount) is 15 g / m ^2, and drying to form a porous ink-receiving layer to prepare an image-receiving sheet. did. Resin mixture composition Aqueous polyurethane resin (trademark: ADEKA BON TITER HUX-401, manufactured by Asahi Denka Co., Ltd.) 100 parts Higher fatty acid amide foam stabilizer (trademark: YC80C, manufactured by Kanebo NSC Co., Ltd.) 5 parts Viscosity control (For thickening) sodium carboxymethyl cellulose (trademark: AG gum, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 15 parts

Example 15 A resin mixture having a composition shown below (viscosity 100,00)
0 cp, solid content concentration 25%) was stirred for 12 minutes with the same stirrer as in Example 1 to prepare a bubble-containing resin mixed solution having a foaming ratio of 4.0. 75m / m2
^On the surface of the high-quality paper of No. ² , coated with an applicator bar so that the coating amount (dry matter amount) is 15 g / m ^2, and dried to form a porous ink-receiving layer, thereby forming an image-receiving sheet. It was made. Resin mixture composition Aqueous polyurethane resin (trademark: ADEKA BON TITER HUX-401, manufactured by Asahi Denka Co., Ltd.) 100 parts Higher fatty acid amide foam stabilizer (trademark: YC80C, manufactured by Kanebo NSC Co., Ltd.) 5 parts Viscosity control (For thickening) Sodium carboxymethyl cellulose (Trademark: AG gum, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 15 parts Sodium polyacrylate for viscosity adjustment (for thickening) (Trademark: Modicol VD-S, San Nopco Ltd.) Made) 5 parts

Comparative Example 1 A resin mixture having the same composition as that of Example 1 was applied to the surface of a high-quality paper of 75 g / m ^{2 with} an applicator bar to give a coating amount (dry matter amount) of 15 g without foaming treatment. / M ² and then dried to form an ink receiving layer, thereby preparing an image receiving sheet.

Comparative Example 2 The foam of Example 1 was coated on a surface of a high-quality paper of 75 g / m ^{2 with} an applicator bar so that the coating amount (dry matter amount) was 1.5 g / m ^2.
m ² was applied and dried to form a bubble-containing layer, which was then dried to form a porous ink-receiving layer to prepare an image-receiving sheet.

Comparative Example 3 A resin mixture having the same composition as in Example 1 was stirred with the same stirrer as in Example 1 at 490 rpm for 30 minutes to give a foaming ratio of 1
A 2.0 times bubble-containing resin mixture was prepared. Immediately after the foaming treatment, the coating amount (dry matter amount) was 5 g / m ² on the surface of a high-quality paper of 75 g / m ² by using an applicator bar.
Was coated and dried to form a porous ink receiving layer, and an image receiving sheet was produced.

Comparative Example 4 A resin mixture having a composition shown below (viscosity 20,000)
(cp, solid content concentration 40%) was subjected to foaming treatment for 25 minutes at 490 rpm using the same stirrer as in Example 1. The expansion ratio was 3.0 times. Resin mixture composition Aqueous polyurethane resin (Trademark: ADEKA BON TITER HUX-401, manufactured by Asahi Denka Co., Ltd.) 100 parts Kaolinite clay (Trademark: HT clay, manufactured by Engelhard) 1000 parts Higher fatty acid alkaline salt type foam stabilizer Agent (Trademark: DC-100A, manufactured by San Nopco Ltd.) 30 parts Sodium carboxymethyl cellulose for viscosity adjustment (for thickening) (Trademark: AG gum, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 10 parts The above-mentioned bubble-containing resin mixture Immediately after foaming the liquid 75 g
/ M ² on the surface of high-quality paper using an applicator bar so that the coating amount (dry matter amount) is 15 g / m ² ,
After drying, a porous ink receiving layer was formed and an image receiving sheet was prepared.

Comparative Example 5 A resin mixture having the composition shown below (viscosity 3,000 c
p, solid content concentration 35%) was stirred for 6 minutes with the same stirrer as in Example 1 to prepare a bubble-containing resin mixed solution having a foaming ratio of 4.0. Immediately after the foaming treatment, it was coated on the surface of a high-quality paper of 75 g / m ² by using an applicator bar so that the coating amount (dry matter amount) was 15 g / m ² , dried, and then porous. An ink receiving layer was formed to prepare an image receiving sheet. Resin mixture composition Aqueous polyurethane resin (trademark: ADEKA BON TITER HUX-401, manufactured by Asahi Denka Co., Ltd.) 100 parts Higher fatty acid amide foam stabilizer (trademark: YC80C, manufactured by Kanebo NSC Co., Ltd.) 5 parts Viscosity control (For thickening) sodium carboxymethyl cellulose (trademark: AG gum, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.5 parts

Test The characteristics of the resin-containing liquid used in Examples 1 to 15 and Comparative Examples 1 to 5 and the image-receiving sheet having the porous ink-receiving layer obtained were measured and evaluated by the following methods. The results are shown in Table 1. [Viscosity measurement method for resin-containing liquid] After mixing various materials with a predetermined composition and adjusting the resin-containing liquid before bubble formation to 23 ° C, a B-type rotational viscometer (trademark: DVL-B type, Tokyo Keiki) The measurement was performed using a No. 3 or No. 4 rotor manufactured by K.K., and a rotation speed of 12 rpm.

[Coatability of Bubble-Containing Resin Liquid] The surface of the bubble-containing resin coating film in a wet state immediately after coating on a support (quality paper) using an applicator bar (coating of the porous ink-receiving layer) The state of (work surface) was observed and evaluated in three grades of ⊚, ◯ and ×. A coating surface that is uniform and has no practical problems ◎, a coating surface that is slightly uneven and is suitable for practical use with no image formation problems, and the coating unevenness is practical Those not suitable were marked with x.

[Expansion Ratio] A container having a fixed volume was filled with the resin liquid before foaming (before foaming) to measure the weight (g), and the same container was filled with the bubble-containing resin liquid after foaming treatment. The weight (g) was measured, and the expansion ratio was calculated by the following formula. Expansion ratio = weight of resin liquid before foaming (g) / weight of resin liquid containing bubbles after foaming treatment (g)

[Measurement Method of Pore Diameter] The pore diameter of the surface of the porous ink receiving layer was measured by taking a photograph of the surface of the receiving layer using a scanning electron microscope or an optical microscope, and then measuring the contour of the pores on the surface. Accurately draw on a transparent film with a black pen, etc., and further, drum scanner (trademark: 260
A 5 type drum scan densitometer (manufactured by Abe Design Co., Ltd.) was used to optically read the contour information of the pores, and the information was measured using an image analyzer (trademark: Luzex III, manufactured by Nireco Corporation). . Since the shape of the pores formed on the surface of the porous ink-receiving layer is not necessarily a perfect circle, the pore diameter should be the equivalent circle diameter based on the area within the contour of the pores obtained by the image analyzer. Converted and displayed.

[Optical Contact Ratio] The optical contact ratio (%) of the surface of the porous ink receiving layer was measured by using Microtopograph (trademark, manufactured by Toyo Seiki Seisakusho Co., Ltd.) and applied pressure: 2
It was measured under the conditions of Kg / cm ² and light wavelength: 0.5 μm.

[Recording Performance] An image-receiving sheet having a porous ink-receiving layer was conditioned at 20 ° C. and 65% relative humidity for one day and then heat transfer color printer (trademark: T
Rueprint 2200, manufactured by Victor Company of Japan, Ltd .: originally an image forming apparatus of sublimation type transfer, but modified so as to also be capable of image formation of a melt transfer system), and an ink image was melt-transfer recorded on the surface thereof. The reflection density of the obtained ink transfer image was measured by a Macbeth reflection densitometer and visually evaluated as described below. (1) Ink image formed with 17 gradations (black monochrome image)
About Macbeth reflection densitometer RD-914 (trademark)
Measure the reflection density for each applied energy using
The highest reflection density and gradation reproducibility were evaluated. Gradation reproducibility is ◎, ○, △, × in the order of good reproduction.
The grade was evaluated. (2) Dot reproducibility is four levels of ◎, ○, △, × in order from the one that is reproduced well as the gradation reproducibility by observing the ink dots transferred from the ink ribbon to the image receiving layer. It was evaluated by. (3) The sharpness of the color image was observed and evaluated in four grades of ⊚, ◯, Δ, and × in order of goodness. In the above evaluation criteria, a level of O or higher is suitable for practical use, and a level of Δ or lower is not suitable for practical use.

[0062]

[Table 1]

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According to the present invention, it is possible to put into practical use a melt transfer ink image-receiving sheet which has good dot reproducibility and gradation reproducibility of a melt transfer ink image and can obtain high recording density, and contributes to the industrial world. There is a lot to do.

Claims (3)

[Claims] 1. A sheet-like support, and a porous ink-receiving layer formed on one surface of the sheet-like support and comprising a porous resin-containing film, wherein the surface of the porous ink-receiving layer is The average pore diameter is in the range of 0.5 to 30 μm, and the porous ink-receiving layer contains 2 kg / cm ²
A melt transfer type ink image-receiving sheet, which has an optical contact ratio in the range of 6 to 65% when pressurized with. 2. The foaming ratio (ratio of the volume after foaming to the volume before foaming, compared with a paint having a constant weight) of a paint in which a resin-containing liquid is mechanically stirred to contain a large number of fine bubbles. The air bubble-containing resin liquid, which is more than 1 time and not more than 10 times, is applied onto one surface of the sheet-shaped support and dried to form a porous ink receiving layer, and the average pore diameter of the surface of the porous ink receiving layer is ,
Melt in the range of 0.5 to 30 μm, and controlling the optical contact ratio in the range of 6 to 65% when the porous ink receiving layer is pressurized at ² Kg / cm ^2. A method of manufacturing a transfer type ink image receiving sheet. 3. The resin-containing liquid has a viscosity of 5,000 to 100,000 c as measured by a B-type rotational viscometer.
The method for producing a melt transfer type ink image-receiving sheet according to claim 2, wherein the range is p.