JPH11180053A - Fusion-transfer type ink image-receiving sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fusion-transfer type ink image-receiving sheet which is excellent in gradation-reproducing property, dot-reproducing property, the clearness of color images, and anti-blocking property, and by which an ink image recording of a high recording density can be obtained. SOLUTION: This fusion-transfer type ink image-receiving sheet has a sheet- like supporting body, and a porous ink image-receiving layer formed of a resin- containing liquid of which the major component is a water-dispersion type resin, on at least one surface of the sheet-like supporting body, and a hardening agent is contained in the resin-containing liquid. It is preferable that the water- dispersion type resin is at least one kind which is selected from a polyurethane resin, an acrylic resin and SBR, and the hardening agent is at least one kind which is selected from dimethylolurea, glyoxal, and zirconium oxide, and in addition, the hardening agent is 1-10 pts.wt. (solid portion) based on 100 pts.wt. (solid portion) of the water-dispersion type resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a melt transfer type ink image receiving sheet. More specifically, when the present invention is used in a fusion transfer type thermal transfer printer using a thermal head, it has excellent gradation reproducibility, dot reproducibility, color image clarity, and blocking resistance, and has a high recording density. The present invention relates to a fusion transfer type ink image receiving sheet capable of obtaining high ink image recording.

[0002]

2. Description of the Related Art A thermal melting transfer recording method using a thermal transfer ink sheet and a thermal head is widely used in printers such as word processors and facsimile machines because of its simple mechanism and easy maintenance. Fine paper has been used as the melt transfer type ink image receiving sheet. However, in recent years, in order to obtain higher gradation reproducibility than before with the full-color thermal transfer recording, printers have changed the size of each dot from the conventional method of obtaining gradation without changing the size of one dot In addition, in the case of the melt transfer type ink image receiving sheet, the dot reproducibility that faithfully reproduces the dot shape of the melt-transferred ink in full-color recording from low applied energy to high applied energy has been improved. It is becoming increasingly important that an excellent and sufficient amount of ink is transferred and the recording density is high as an important quality of a recorded image.

[0003] In order to make the thermal transfer image full-color as described above, it is necessary to appropriately cope with the characteristics of the melt transfer type ink image receiving sheet. That is, when using uncoated paper for normal printing in the full-color hot-melt transfer system,
In some cases, the recording density may be reduced due to low heat insulation, and the dot reproducibility may be poor due to insufficient cushioning properties. Also, if the surface is too rough, a phenomenon that causes a portion where the ink is not transferred, that is, a drop occurs, or if the surface is too smooth, the anchoring effect of the ink becomes insufficient and the transferred ink is Is easily transferred to the ink ribbon, that is, the ink is easily transferred. Any of these causes a poor dot reproducibility. In addition to the decrease in recording density due to the poor dot reproducibility as described above, a decrease in recording density due to low ink absorbency of the molten ink 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 sheet-like support (JP-A-2-89690, JP-A-64-27996). Gazette). However, this attempt is still insufficient in improving the cushioning property and the heat insulating property of the melt transfer type ink image receiving sheet. In addition, in this attempt, when the hollow particles are dissolved in an organic solvent or the like of the receiving layer, a polymer material having organic solvent resistance is used as an adhesive for the hollow particles, or on the layer containing the hollow particles. It is necessary to provide a polymer layer having resistance to organic solvents, which raises a problem in production.

[0005] As another attempt to solve the above problem, a sheet-like support mainly composed of plastic is provided on a sheet-like support.
It has also been proposed to form a resin layer containing a component eluted in water, elute and remove water-soluble components from the resin layer to form micropores, thereby improving the ink receiving capacity of the melt transfer type ink image receiving sheet. (JP-A-2-412)
No. 87). However, in this case, there is a disadvantage that the maximum density is still insufficient, or the printed image is not glossy.
It has not yet been able to satisfy the increasing required quality of the melt transfer type ink image receiving sheet. Further, since the melt transfer type ink image receiving sheet is mainly composed of plastic, it is difficult to recycle.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art, and to provide gradation reproducibility, dot reproducibility, clearness of a color image, and An object of the present invention is to provide a melt transfer type ink image-receiving sheet having excellent blocking resistance and capable of obtaining an ink image having a high recording density.

[0007]

Means for Solving the Problems A melt transfer type ink image receiving sheet according to the present invention comprises a sheet-like support, and a porous sheet formed on at least one surface thereof from a resin-containing liquid containing a water-dispersible resin as a main component. And a hardening agent in the resin-containing liquid.
It is preferable that the water-dispersed resin is at least one selected from polyurethane resins, acrylic resins, and SBR. Further, the curing agent is at least one selected from dimethylol urea, glyoxal, and zirconium oxide.
Preferably, the curing agent is 1 to 10 parts by weight (solid content) based on 100 parts by weight (solid content) of the water-dispersible resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive studies to achieve the above object, the present inventor has found that, in recording with a fusion heat transfer printer, a resin-containing liquid containing a water-dispersible resin as a main component is formed. By using a melt transfer type ink image receiving sheet having a porous ink receiving layer containing a curing agent and formed with fine bubbles, dot reproducibility, gradation reproducibility, color image clarity, etc. are excellent. The inventors have found that density recording can be realized, and have completed the present invention.

In the present invention, the porous ink receiving layer formed on the sheet-like support contains a water-dispersible resin and, if necessary, a pigment as a main component. Such a porous ink receiving layer is formed by subjecting a liquid material containing a water-dispersed resin, a curing agent, and a pigment, if necessary, to mechanical stirring to form a large number of fine air bubbles therein, thereby dispersing and containing the air bubbles. The resin solution can be formed by coating and drying the resin solution on the sheet-like support.

In the present invention, the curing agent is used for forming the porous ink receiving layer when the bubble-containing resin liquid is dried, that is, when the pores are formed from the bubbles, the bubble-containing resin liquid is immobilized early. Thereby, coalescence of bubbles is suppressed, and as a result, pores on the surface and inside of the porous ink receiving layer are made fine. Further, since the porous ink receiving layer is cured, there is also a secondary effect that the blocking resistance is improved.

In the present invention, the curing agent used for forming the porous ink receiving layer reacts with the water-dispersible resin, the thickener, and the like in the bubble-containing resin liquid and contributes to the formation of a crosslinked structure. . Examples of the curing agent that can be used in the present invention include dimethylol urea, glyoxal, formaldehyde, epoxy compounds, and aziridine compounds, and metal salts such as zirconium oxide and zinc sulfate, but are not limited thereto. Absent. For example,
Dimethylol urea is a water-soluble resin having a hydroxyl group such as polyvinyl alcohol, starch and derivatives thereof, and metal salts such as zirconium oxide and zinc sulfate.
It easily reacts with a water-dispersed resin having a carboxylate or a sulfonate, such as an SBR latex, an acrylic resin or a self-emulsifying polyurethane resin. In addition, glyoxal reacts with any of a hydroxyl group, a carboxylate and a sulfonate. These curing agents can be used alone or as a mixture of two or more, if necessary. Specific examples of the curing agent used in the present invention include Papyrrole J-001, Papyrrole J-003, and Papyrrole J-016 manufactured by Showa Denko KK, and Baycoat 20 manufactured by Nippon Metal Co., Ltd.

The amount of the curing agent used is generally 1 to 10 parts by weight of the solid content of the curing agent per 100 parts by weight of the solid content of the water-dispersible resin liquid or the mixture of the water-dispersible resin liquid and the pigment. And more preferably 3 to 6 parts by weight. When the addition amount of the curing agent is less than 1 part by weight, the effect of suppressing coalescence of bubbles is not sufficient, and it is difficult to form micropores. Even if the added amount of the curing agent exceeds 10 parts by weight, the effect is saturated, and it is economically disadvantageous. Also, the curing of the porous ink receiving layer progresses too much, the bonding strength in the porous ink receiving layer decreases, and when an image is formed, troubles such as peeling of the porous ink receiving layer occur, A good image may not be formed.

In the present invention, the term “water-dispersible resin” used for forming the porous ink-receiving layer refers to an interface containing a hydrophilic functional group in the skeleton of a molecular chain or an interface such as an emulsifier added during synthesis. Polymers or oligomers such as aqueous emulsions and colloidal dispersions (microemulsions) that are stably dispersed in water as a medium due to the effect of the activator. As the water-dispersible resin usable in the present invention,
For example, polyurethane resin, urethane-acrylic copolymer, styrene-butadiene copolymer (SBR latex), acrylonitrile-butadiene copolymer (NBR)
Latex), methyl methacrylate-butadiene copolymer (MBR latex), styrene-acryl copolymer, polyacrylate, polymethacrylate, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer Examples include, but are not limited to, polymers, polyvinylidene chloride, and the like. These water-dispersed resins can be used alone or as a mixture of two or more, if necessary.

The above-mentioned water-dispersible resin and various known aqueous resins can be mixed and used in accordance with the required level of the recording performance or the suitability of the recording apparatus. That is, one or more types of aqueous resins as exemplified below can be used in combination with the water-dispersible resin. For example, polyvinyl alcohols and derivatives thereof of various molecular weights and degrees of saponification, various modified starches such as starch and oxidized starch, cellulose derivatives such as methoxycellulose, carboxymethylcellulose, methylcellulose and ethylcellulose, and water-soluble resins such as polyethylene glycol Further, glue, casein, soy protein, gelatin, sodium alginate and the like can be used, but are not limited thereto.

In the present invention, examples of the pigment which can be contained in the porous ink receiving layer include zinc oxide, titanium oxide, calcium carbonate, silicic acid, silicate, clay, talc, mica, calcined clay, and aluminum hydroxide. , Barium sulfate, lithopone, inorganic pigments such as colloidal silica, polystyrene, polyethylene, polypropylene, epoxy resin, spheres such as styrene-acrylic copolymers, hollow, or referred to as plastic pigments processed into various shapes Organic pigments, starch powder, cellulose powder and the like can be used,
It is not limited to these. These pigments can be used alone or as a mixture of two or more, if necessary.

The porous resin coating film of the present invention, as inferred from its structure, cannot be said to have inherently high coating film strength. Therefore, blending various pigments further reduces the coating film strength. As a result, troubles such as image peeling may occur as described above. Therefore, when the porous ink receiving layer is formed by adding various pigments to the water-dispersed resin-containing liquid, the mixing amount is appropriately determined in consideration of the overall quality of the melt transfer type ink image receiving sheet. You can decide. In the liquid material containing the resin or the mixture of the resin and the pigment before the formation of the bubbles, a known viscosity modifier, a dispersant, a dye, a waterproofing agent, a lubricant, a plasticizer, and the like can be added as necessary. .

A porous ink formed on a sheet-like support
The coating amount of the receiving layer is 2 to 40 g / m ^TwoPreferably
New Coating amount 2g / m^TwoIf less, sheet
It is difficult to sufficiently cover the roughness of the surface of the support
In many cases, the surface of the
Ink receiving sheet cannot be obtained,
Shrink deformation may not be obtained. On the other hand, it is 40g /
m^TwoIf it exceeds the thickness, the thickness of the porous ink receiving layer
Is too large and the bonding strength in the porous ink receiving layer is low.
When the image is formed, the porous ink receiving layer
Good images can be formed due to troubles such as peeling
Not always. The coating amount of the porous ink receiving layer is necessary
What is necessary is just to select suitably according to performance.

In the present invention, the porous ink-receiving layer comprises a water-dispersible resin liquid or a liquid mixture containing a water-dispersible resin and a pigment as main components containing a large number of microbubbles. It can be obtained by coating on top and drying. There is no particular strict restriction on the method, equipment and coating method for forming and containing bubbles.

In the production of the porous ink receiving layer according to the present invention, a resin-containing liquid before forming and dispersing bubbles by mechanical stirring is subjected to a B-type rotational viscometer.
The viscosity measured at 500C is 500 to 50,000 cps.
Is preferably in the range of 1000 to 20000 c
When it is in the range of ps, more preferable results are obtained. When the viscosity of the resin-containing liquid is less than 500 cps, the stability of the bubbles formed and dispersed by the mechanical stirring treatment is deteriorated, so that the bubbles are easily broken or the bubbles are united, and the fine bubbles are hardly retained. is there. 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 melt transfer type ink receiving sheet may be reduced. As the viscosity of the resin-containing liquid before mechanical stirring is increased, the size of the bubbles dispersed in the liquid becomes finer. However, when the viscosity exceeds 50,000 cps, there is no problem in the stability of the bubbles, but the formation and dispersion of the bubbles are performed. Because the viscosity of the foamed resin-containing liquid increases further than before the stirring treatment, the coatability on one surface of the sheet-like support deteriorates, and problems such as uneven coating may occur. is there. In addition, since the energy consumed for the mechanical stirring treatment becomes excessive, it is disadvantageous from the viewpoint of economy and energy saving.

The bubble-containing state of the water-dispersed resin-containing liquid containing bubbles is not particularly limited, but preferably, the expansion ratio (the volume ratio of the bubble-containing liquid to the stock solution as compared with a paint having a constant weight) is preferable. It is preferably more than 1 and less than 10 times, more preferably more than 1 and less than 5 times. That is, the foaming ratio is a measure of the bubble content in the bubble-containing water-dispersed resin-containing liquid, and means that as the foaming ratio increases, the thickness of the resin film (wall) constituting the bubbles decreases. . As described above, when the resin film is thin, it may be difficult to maintain the strength of the obtained porous ink receiving layer at a sufficient level, and the expansion ratio may vary depending on the balance with the composition of the aqueous dispersion type resin-containing mixed liquid. What is necessary is just to select suitably according to required performance.

The mechanism by which the melt transfer type ink image-receiving sheet of the present invention exhibits excellent melt ink transfer suitability involves the physical characteristics such as the structural characteristics and compression characteristics of the porous ink receiving layer and the melt transfer type ink image receiving sheet. It is thought that it is doing. In terms of structural characteristics, the surface of the porous ink receiving layer formed on the sheet-like support has a large number of fine holes, so that there is absorption of molten ink by capillary force, Since the large number of pores contained in the porous ink receiving layer communicate with each other to form open cells, the permeability of the molten ink into the porous ink receiving layer is improved, and a high ink receiving property is obtained. It is thought that it expresses ability.

In this regard, the size of the pores on the surface of the porous ink receiving layer formed on the melt transfer type ink receiving sheet is related to the ink receiving capacity. That is, in order to form a good image on the melt transfer type ink receiving sheet of the present invention when the molten ink is transferred, the average pore diameter of the surface of the porous ink receiving layer is in the range of 0.5 to 30 μm. Preferably, more preferably 1.0 to 20 μm
And more preferably in the range of 1.0 to 5 μm.

The pore diameter is related to its size, ie, its ability to capture molten ink by capillary action due to its size, with smaller pores having greater capacity. However, when the average pore diameter is less than 0.5 μm, the ink absorbing ability is poor, and transfer failure may occur. On the other hand, when the average pore diameter is larger than 30 μm and the pore size is excessive, the transfer ink is buried in the pores, and poor transfer between the ink ribbon and the porous ink image receiving layer surface is hindered. This may cause transfer unevenness and may cause defective dot reproduction, making it impossible to form a good image. The pore diameter on the surface of the porous ink image-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 water-dispersible resin-containing mixed liquid before the bubble formation / dispersion treatment, ie, the kind of the material, the mixing ratio, the bubbles, the coating, and the film in the porous ink receiving layer after drying. It is often affected by the amount remaining as a component directly related to the thickness, or various factors such as the above-mentioned expansion ratio and coating method, and may be appropriately selected according to the required performance. 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 bubble-containing resin liquid obtained by mechanical stirring, and generally, the smaller the bubbles in the resin-containing liquid, Since the pores on the surface of the porous ink receiving layer after coating and drying are also reduced, the bubble-containing state of the aqueous dispersion type resin-containing mixture is not particularly limited, but is the same as the surface of the porous ink receiving layer. It is preferable that fine bubbles having a size, that is, an average diameter of 0.5 to 30 μm are dispersed and mixed, more preferably, an average diameter is in a range of 1.0 to 20 μm, and further preferably, an average diameter is 1. It is in the range of 0-5 μm. The size of the contained bubbles can be measured with an image analyzer by photographing a part of the bubbles with an optical microscope.

In the present invention, the method for forming, containing and dispersing air bubbles in a water-dispersed resin-containing liquid is used, for example, in a so-called confectionery foaming machine having a stirring blade rotating while carrying out planetary motion, generally emulsified dispersion and the like. A homomixer, a stirrer such as a Cowles dissolver, or a device capable of dispersing and mixing air into fine bubbles by mechanically stirring while continuously feeding air and a mixture of a resin-containing liquid into a closed system,
For example, a continuous foaming machine such as Gaston County in the United States and Stoke in the Netherlands can be used, but there is no strict limitation. In addition, due to the insufficient capacity of the equipment for mechanical stirring, a desired bubble-containing state cannot be obtained, or a foam stabilizer is used for the purpose of improving the stability of bubbles in the bubble-containing resin liquid. And a wide range of surfactants referred to as foaming agents.

Examples of such surfactants include higher fatty acids, modified higher fatty acids, and alkali salts of higher fatty acids.
In particular, the water-dispersible resin-containing liquid has a high foaming effect and a high effect of improving the stability of the dispersed and contained bubbles, so that it can be used. There is no particular limitation on the selection, but there is no particular limitation except for a material that may significantly impair the fluidity of the aqueous dispersion-type resin-containing mixture or impair coating workability. Further, the amount of the surfactant such as the above foam stabilizer and foaming agent is used, based on 100 parts by weight of the solid content of the aqueous dispersion type resin liquid or the mixed liquid of the aqueous dispersion type resin liquid and the pigment.
The surfactant solid content is preferably from 0 to 30 parts by weight, more preferably from 1 to 20 parts by weight. Even if the amount of the surfactant added is more than 30 parts by weight, the effect is saturated and the economical disadvantage is often caused.

The coating method for forming the porous ink receiving layer on the sheet-like support includes a Meyer bar method,
The method can be arbitrarily selected from known methods such as a gravure roll method, a roll method, a reverse roll method, a blade method, a knife method, an air knife method, an extrusion method, and a cast method.

The melt-transfer type ink image-receiving sheet having the porous ink-receiving layer of the present invention can exhibit a good melt thermal transfer image even when the bubble-containing resin liquid is applied to a sheet-like support and left dry. Yes, but the metal roll 2
Finish treatment of this porous ink receiving layer using a machine calender composed of multiple steps or a super calender composed of a metal roll and a resin roll, or a metal roll and a cotton roll appropriately combined Is performed to further improve the smoothness of the surface. After coating, the surface of the porous ink receiving layer of the semi-dry or dry sheet is brought into contact with a mirror-finished heated or non-heated cast drum or the like to improve its surface smoothness. May be. However, when the above-mentioned smooth finishing treatment is performed under excessive pressure, the resin wall surrounding the bubbles in the porous ink receiving layer is broken, and the porous ink receiving layer is densified, and the heat insulating property and the cushioning property are reduced or Since the pores on the surface of the porous ink receiving layer are deformed or destroyed, the excellent molten ink transfer performance of the porous ink receiving layer may not be obtained. Therefore, the above-mentioned smooth finishing conditions may be appropriately selected according to the required performance.

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

Further, when the water-containing resin liquid containing bubbles is applied on the above-mentioned sheet-like support to produce the melt-transfer-type ink image-receiving sheet of the present invention, in the steps of coating, drying and winding, etc. Then, the melt transfer type ink image receiving sheet itself curls with its porous ink receiving coating layer inside or outside. In this case, if the melt transfer type ink image-receiving sheet is used after being processed into an image forming sheet of a predetermined size by cutting, paper feeding to a thermal transfer printer may not be performed normally, or runnability inside the printer may be reduced. Troubles such as deterioration may occur. Further, since the melt transfer recording method is a method in which a heat source is brought into contact with an ink ribbon and a dye component in the ribbon is transferred onto a melt transfer type ink receiving sheet, a porous ink receiving layer which is an image forming surface and a sheet-like support are provided. Due to the difference in shrinkage characteristics or expansion characteristics due to heating of the body layer, the melt transfer type ink image receiving sheet curls inside the apparatus, and the above-described 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 in the sheet inside the apparatus, so that the contact between the ink ribbon and the melt transfer type ink image receiving sheet is normal. Is not performed at the same time, an ink transfer failure occurs, and as a result, image quality may be deteriorated.

In order to prevent various troubles caused by such curling, it is necessary to minimize the difference in shrinkage characteristics or expansion characteristics between the porous ink receiving layer and the sheet-like support layer due to heating. desirable. For this purpose, an anti-curl layer may be applied or laminated on the back surface of the sheet-shaped support, that is, on the surface opposite to the porous ink receiving layer. There is no limitation on the material, forming method, coating amount, laminating amount, etc. of the curl prevention layer, and the type, thickness or properties of the porous ink receiving layer, that is, material composition, expansion ratio, coating Optimization can be achieved in consideration of various factors such as the amount of work.

Further, depending on the material selection of the sheet-shaped support, when the obtained melt-transfer-type ink image-receiving sheet travels inside the printer, it receives various frictional forces due to the mechanism of the apparatus, or the humidity inside the apparatus decreases due to heating. The melt transfer type ink image-receiving sheet may be charged with static electricity by the influence of the above or the like alone or in combination. When a large number of images are continuously formed in such a state, the image forming surface of the melt transfer type ink image receiving sheet and the back surface of the next melt transfer type ink image receiving sheet are electrostatically adhered to each other and are difficult to peel. . In particular, since various types of plastic sheets or synthetic paper have a property of being easily charged in nature, when using them as a sheet-like support, static electricity is required during the sheeting process by cutting or during storage after processing. Due to the occurrence, it is difficult for the front and back of the sheet to peel off. As a matter of course, even when paper is used as the sheet-like support, the above-described trouble can occur. In order to prevent troubles caused by such charging,
It is very effective to form a so-called antistatic layer on the back surface of the melt transfer type ink image receiving sheet. Charging can be achieved by using an antistatic material or by reducing the coefficient of friction between the back surface of the sheet-like support layer and the sheet between the porous ink receiving layer. Therefore, the antistatic layer can be formed by appropriately selecting from a wide range of materials and methods similarly to the formation of the anticurl layer.

The anti-curl layer and anti-static layer can be individually formed on the back surface of the sheet-like support to obtain the desired performance, but the production process can be simplified, the production cost can be reduced, or By appropriately selecting a material and a forming method as needed according to an intended functional level or the like, the object can be achieved by forming a single layer. That is, it is possible to provide trouble prevention performance such as curling prevention and antistatic with a single layer. Therefore, there is no limitation on the number of layers formed on the back surface of the sheet-like support.

[0034]

EXAMPLES The present invention will be described more specifically with reference to the following Examples, but the present invention is not limited by these. In the examples and comparative examples, all “parts” represent “parts by weight based on the solid content of the water-dispersible resin”.

Example 1 A water-dispersed polyurethane resin liquid (solid content: 25% by weight) having the following composition was used in a continuous foaming machine (trade name: Turbo Hop TW-70, manufactured by Aikosha Seisakusho). The foaming treatment was performed at a stirring speed of 1500 rpm and a foaming ratio of 3.0. Resin mixture liquid composition 1 Water-dispersed polyurethane resin: (trademark: NeoRez R-960, manufactured by Zeneca) 100 parts Higher fatty acid-based foam stabilizer: (trademark: SN foam 200, manufactured by San Nopco) 5 parts For viscosity control (increase) Viscosity agent) Sodium carboxymethyl cellulose: (trademark: AG gum, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 2 parts Curing agent: dimethylol urea: (trademark: papyrol J-001, manufactured by Showa Denko KK) 5 parts Immediately after the foaming treatment, the coated paper is coated on a surface of a high-quality paper having a basis weight of 75 g / m ² using an applicator bar so that the coated amount after drying is 10 g / m ^2, and dried to obtain a porous material. An ink receiving layer was formed to prepare a melt transfer type ink image receiving sheet.

Example 2 A water-dispersed polyurethane resin liquid (solid content: 25% by weight) having the following composition was used in a continuous foaming machine (trade name: Turbo Hop TW-70, manufactured by Aikosha Seisakusho). The foaming treatment was performed at a stirring speed of 1500 rpm and a foaming ratio of 3.0. Resin mixture liquid composition 2 Water-dispersed polyurethane resin: (trademark: NeoRez R-960, manufactured by Zeneca) 100 parts Higher fatty acid-based foam stabilizer: (trademark: SN foam 200, manufactured by San Nopco) 5 parts For viscosity control (increase) Viscosity agent) Sodium carboxymethyl cellulose: (trademark: AG gum, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2 parts Curing agent: glyoxal: (trademark: papyrrole J-003, manufactured by Showa Denko KK) 5 parts Immediately after the foaming treatment, the surface of a high-quality paper having a basis weight of 75 g / m ² was coated using an applicator bar so that the coated amount after drying was 10 g / m ^2, and dried to obtain a porous ink. A receptor layer was formed to prepare a melt transfer type ink image receiving sheet.

Example 3 An aqueous dispersion type polyurethane resin liquid (solid content: 25% by weight) having the following composition was used in a continuous foaming machine (trade name: Turbo Hop TW-70, manufactured by Aikosha Seisakusho). The foaming treatment was performed at a stirring speed of 1500 rpm and a foaming ratio of 3.0. Resin mixture composition 3 Water-dispersed polyurethane resin: (trademark: NeoRez R-960, manufactured by Zeneca) 100 parts Higher fatty acid-based foam stabilizer: (trademark: SN foam 200, manufactured by San Nopco) 5 parts For viscosity adjustment (increase) Viscosity agent) Sodium carboxymethyl cellulose: (trademark: AG gum, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2 parts Curing agent: zirconium oxide: (trademark: Baycoat 20, manufactured by Nippon Light Metal Co., Ltd.) 5 parts Foaming the above resin mixture containing cells Immediately after the treatment, the surface of a high-quality paper having a basis weight of 75 g / m ² is coated using an applicator bar so that the coating amount after drying is 10 g / m ² , dried, and dried to receive a porous ink. A layer was formed to prepare a melt transfer type ink image receiving sheet.

Example 4 A water-dispersed acrylic resin-containing liquid (solid content: 25% by weight) having the following composition was used in a continuous foaming machine (trade name: Turbo Hop TW-70, manufactured by Aikosha Seisakusho). Then, a foaming treatment was performed at a stirring speed of 1500 rpm to a foaming ratio of 3.0 times. Resin mixture composition 4 Water-dispersed acrylic resin: (trademark: Bonron S-1320, manufactured by Mitsui Chemicals) 100 parts Higher fatty acid-based foam stabilizer: (trademark: SN foam 200, manufactured by San Nopco) 5 parts For viscosity control ( Thickener) Sodium carboxymethylcellulose (trademark: AG gum, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2 parts Curing agent: dimethylol urea: (trademark: papyrol J-001, manufactured by Showa Denko KK) 5 parts Immediately after the foaming treatment, the coated paper is coated on a surface of a high-quality paper having a basis weight of 75 g / m ² using an applicator bar so that the coated amount after drying is 10 g / m ^2, and dried to obtain a porous material. An ink receiving layer was formed to prepare a melt transfer type ink image receiving sheet.

Example 5 A water-dispersible acrylic resin-containing liquid (solid content: 25% by weight) having the following composition was used in a continuous foaming machine (trade name: Turbo Hop TW-70, manufactured by Aikosha Seisakusho). Then, a foaming treatment was performed at a stirring speed of 1500 rpm to a foaming ratio of 3.0 times. Resin mixture composition 5 SBR latex: (trademark: L-1225, manufactured by Asahi Kasei Corporation) 100 parts Higher fatty acid-based foam stabilizer: (trademark: SN foam 200, manufactured by San Nopco) 5 parts For viscosity control (thickener) Carboxymethylcellulose sodium (trademark: AG gum, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2 parts Curing agent: dimethylol urea: (trademark: papyrol J-001, manufactured by Showa Denko KK) 5 parts After the above foam-containing resin mixed solution is subjected to foaming treatment Immediately, the surface of a high-quality paper having a basis weight of 75 g / m ² was coated using an applicator bar so that the coating amount after drying was 10 g / m ^2, and dried to form a porous ink receiving layer. Thus, a melt transfer type ink image receiving sheet was prepared.

Comparative Example 1 A water-dispersible polyurethane resin-containing liquid (solid content: 25% by weight) having the following composition was mixed with a continuous foaming machine (trade name:
Using a turbo hop TW-70 (manufactured by Aikosha Seisakusho Co., Ltd.), a foaming treatment was performed at a stirring speed of 1500 rpm to a foaming ratio of 3.0. Resin mixture composition 6 Water-dispersed polyurethane resin: (trademark: NeoRez R-960, manufactured by Zeneca) 100 parts Higher fatty acid-based foam stabilizer: (trademark: SN foam 200, manufactured by San Nopco) 5 parts For viscosity control (increase) Viscous agent) sodium carboxymethylcellulose: (trademark: AG gum, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2 parts Immediately after the foaming treatment of the above-mentioned bubble-containing resin mixture, an applicator is applied on the surface of high-quality paper having a basis weight of 75 g / m ^2. Coating was performed using a bar so that the coating amount after drying was 10 g / m ^2, and the coating was dried to form a porous ink receiving layer, thereby producing a melt transfer type ink image receiving sheet.

Comparative Example 2 A water-dispersed acrylic resin-containing liquid (solid content: 25% by weight) having the following composition was used in a continuous foaming machine (trade name: TurboWhip TW-70, manufactured by Aikosha Seisakusho). Then, a foaming treatment was performed at a stirring speed of 1500 rpm to a foaming ratio of 3.0 times. Resin mixture liquid composition 7 Water-dispersed acrylic resin: (trademark: Bonron S-1320, manufactured by Mitsui Chemicals) 100 parts Higher fatty acid-based foam stabilizer: (trademark: SN Foam 200, manufactured by San Nopco) 5 parts For viscosity control ( Thickener) sodium carboxymethylcellulose: (trademark: AG gum, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2 parts Immediately after the foaming treatment of the above bubble-containing resin mixture, on the surface of high-quality paper having a basis weight of 75 g / m ^2. Coating was performed using an applicator bar so that the coating amount after drying was 10 g / m ^2, and the coating was dried to form a porous ink receiving layer, thereby producing a melt transfer type ink image receiving sheet.

Comparative Example 3 A water-dispersed acrylic resin-containing liquid (solid content: 25% by weight) having the following composition was used in a continuous foaming machine (trade name: Turbo Hop TW-70, manufactured by Aikosha Seisakusho). Then, a foaming treatment was performed at a stirring speed of 1500 rpm to a foaming ratio of 3.0 times. Resin mixture composition 8 SBR latex: (trademark: L-1225, manufactured by Asahi Kasei Kogyo) 100 parts Higher fatty acid-based foam stabilizer: (trademark: SN foam 200, manufactured by San Nopco) 5 parts For viscosity control (thickener) Sodium carboxymethylcellulose (trademark: AG gum, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2 parts Immediately after the foaming treatment of the above-mentioned bubble-containing resin mixture liquid, using an applicator bar on the surface of a high-quality paper having a basis weight of 75 g / m ^2. Coating was performed so that the coating amount after drying was 10 g / m ^2, and the coating was dried to form a porous ink receiving layer, thereby producing a melt transfer type ink image receiving sheet.

Evaluation Method The properties of the water-dispersible resin used in the examples and comparative examples, and the obtained melt transfer type ink image-receiving sheet having the porous ink-receiving layer were measured and evaluated by the following methods. Table 1 shows the evaluation results.

[Measurement Method of Pore Diameter] The pore diameter of the surface of the porous ink receiving layer is determined by taking a photograph of the surface of the receiving layer using a scanning electron microscope or an optical microscope, and then defining the outline of the pores on the surface. Draw accurately on a transparent film with a black pen or the like, and further, use a drum scanner (trademark: 260
5 Drum Scan Densitometer, Abe Design Co., Ltd.)
, Optically reads the information on the outline of the pores, and reads this information using an image analyzer (trade name: Luzex III, manufactured by Nireco).
It measured using. The shape of the pores formed on the surface of the porous ink receiving layer is not necessarily a perfect circle, so the pore diameter is converted into a circle equivalent diameter based on the area within the contour of the pore obtained by image analysis. displayed.

[Recording performance] The melt transfer type ink image-receiving sheet having the porous ink-receiving layer obtained in Examples 1 to 5 and Comparative Examples 1 to 3 was 20 ° C. and a relative humidity of 65%.
And then supply it to a thermal transfer color printer (trademark: Trueprint2200, manufactured by Victor Company of Japan, originally a sublimation transfer image forming apparatus, but modified to enable the formation of a melt transfer type image). Then, an ink image was melt-transfer-recorded on the surface. The reflection density of the obtained ink transfer image was measured with a Macbeth reflection densitometer and evaluated visually as described below. In the following evaluation criteria, the ○ level is good and suitable for practical use, but the △ and × levels are insufficient and not practical. (1) Ink image formed with 17 gradations (black monochrome image)
About Macbeth reflection densitometer RD-914 (trademark)
The reflection density is measured for each applied energy using
The maximum reflection density and gradation reproducibility were evaluated. The gradation reproducibility was evaluated in three steps of ○, Δ, and × in order from the one reproduced well. (2) The dot reproducibility is evaluated by observing the dots of the ink transferred from the ink ribbon to the receiving layer, and in the order of good reproducibility in the same manner as the gradation reproducibility, in the order of ○, Δ, ×. did. (3) The sharpness of the color image was observed, and the evaluation was made in three steps of ○, Δ, and × in order of good quality. (4) The peeled state was evaluated by observing the image formed on the receiving layer, and in the order of good, no peeling of the ink, ○, Δ,
The evaluation was made in three stages of x.

[Blocking resistance]
On a stainless steel plate (10 cm square)
The porous ink receiving layer and the sheet of the fusion transfer type ink image receiving sheet
10 sheets so that the back side of the support is in contact with the back
After combining, 1cm of the melt transfer type ink image receiving sheet ^Two This
Mirror finish so that a load of 50 g is applied.
A stainless steel plate (10 cm square) and a weight were placed. In this state
Maintained at 50 ° C. and relative humidity of 80% for 24 hours
After that, the porous ink receiving layer and the back surface of the sheet-like support are
A, B, C
Was evaluated in three steps. A: no resistance B: very little resistance, but porous
There is no damage to the recording layer and there is no practical problem in recording performance.
None C: High resistance, it looks like glued, porous
The ink receiving layer is destroyed and is not suitable for practical use

[0047]

[Table 1]

In the porous ink receiving layer composed of a resin-containing liquid containing a water-dispersible resin as a main component, fine pores are formed by using a curing agent in combination with the resin-containing liquid (Examples 1 to 5). As a result, it was found that a high reflection recording density was obtained. As a secondary effect, the blocking resistance was also improved by the curing of the porous ink receiving layer.

[0049]

According to the present invention, it is possible to practically use a melt transfer type ink image receiving sheet having a high recording density, and excellent in gradation reproducibility, dot reproducibility, color clarity and blocking resistance. The place that contributes is great.

Claims (4)

[Claims] 1. A melt-transfer-type ink image-receiving sheet comprising a sheet-like support and, on at least one surface thereof, a porous ink-receiving layer formed from a resin-containing liquid containing a water-dispersible resin as a main component. A melt transfer type ink image receiving sheet comprising a resin-containing liquid containing a curing agent. 2. The melt-transfer-type ink image-receiving sheet according to claim 1, wherein the water-dispersible resin is at least one selected from a polyurethane resin, an acrylic resin, and SBR. 3. The ink sheet according to claim 1, wherein the curing agent is at least one selected from dimethylol urea, glyoxal, and zirconium oxide. 4. The melt transfer type ink image receiving sheet according to claim 1, wherein the curing agent is used in an amount of 1 to 10 parts by weight (solid content) based on 100 parts by weight (solid content) of the water-dispersible resin.