JPH05177964A - Image receive sheet for thermal transfer recording - Google Patents

Abstract

PURPOSE:To improve record sensitivity and record quality of image receive sheet for thermal transfer recording which utilizes heat sublimating dye. CONSTITUTION:In an image receive sheet for thermal transfer recording, an image receiving layer for receiving a transfer image from a color material transfer sheet is provided on a support body. Between the image receiving layer and the support body, an intermediate layer containing resin fine-grain with a multi-layer structure of 3 layers or more having an internal air layer is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image-receiving sheet for thermal transfer recording, and more particularly to an improvement of an image-receiving sheet for thermal transfer recording using a heat sublimation dye, which has a remarkably improved recording sensitivity and recording image quality. Is provided.

[0002]

2. Description of the Related Art The thermal recording system, which can obtain a recorded image at the same time as an input signal, is used in various fields such as facsimiles, computer terminal printers, and measuring instrument printers because it is relatively simple and inexpensive and has low noise. Has been done. As a recording medium used in these thermal recording systems, a so-called color-developing type heat-sensitive recording paper is most commonly used, which is provided with a recording layer that undergoes a physical or chemical change by heating to develop a color.

However, the color-developing type thermosensitive recording paper is liable to cause unnecessary color development during the manufacturing process and during storage, and is also inferior in the storage stability of the recorded image, so that it is compatible with organic solvents and chemicals. There is a drawback that fading phenomenon is easily caused by contact. Therefore, as a recording medium replacing the color-developing thermosensitive recording paper, a method using a recording medium using a colored coloring material itself has been proposed, for example, Japanese Patent Laid-Open No. 51-1.
Japanese Patent No. 5446 discloses a thermal recording head in which a coloring material that is solid or semi-solid at room temperature is coated on a support such as paper or polymer film, and the coloring material on the support is brought into contact with the recording paper. Has proposed a method in which a coloring material on a support is heated and selectively transferred to a recording paper to obtain a recorded image.

In this recording method, the coloring material on the support is melted, evaporated and sublimated by heat and transferred to recording paper,
A recorded image is obtained by adhesion, adsorption, and dyeing, and plain paper can be used as recording paper. In particular, in a recording method using a sublimable dye as a coloring material, an image excellent in gradation can be obtained, and therefore application development for full-color recording is being advanced.

However, when plain paper is used as the recording paper, dyeing is difficult to occur, sufficient color density is difficult to obtain, and a marked fading phenomenon occurs over time. Therefore, JP-A-57-107885 and US Pat.
An image receiving sheet having an image receiving layer containing a thermoplastic resin as a main component is proposed in Japanese Patent No. 01484. By forming an image receiving layer containing a thermoplastic resin as a main component,
Recording sensitivity and storability are improved for the time being, but especially when the support is plain paper, a uniform image receiving layer cannot be obtained, and the recording sensitivity,
The image quality was insufficient. Therefore, JP-A-60-2
As described in JP-A-36794 and JP-A-61-144394, an intermediate layer such as a thermoplastic resin is interposed between a support and an image receiving layer, and a coloring material of a coloring material transfer sheet is used at the time of printing. There has been proposed a method for improving the recording sensitivity and the image quality by improving the close contact between the layer and the image receiving layer of the image receiving sheet so that an air gap is not generated. Further, it has been proposed that the intermediate layer be made of resin fine particles made of a specific thermoplastic resin to further improve the image quality (Japanese Patent Laid-Open No. 63-63).
-87286, JP-A- 64-27996, JP-A-1
-136784, JP-A-2-139293). However, in reality, none of them has achieved satisfactory image quality.

On the other hand, it has been proposed to obtain good image quality and recording sensitivity by using a synthetic paper or a white film as a support, but it is deformed by heat applied during recording, and is expensive. There are still problems such as the material, and I was not satisfied with it.

[0007]

In view of the above situation, the present inventors have earnestly studied for improvement of an image-receiving sheet for thermal transfer recording, which is useful in a recording system in which a colored coloring material, particularly a heat sublimable dye, is thermally transferred. As a result, the recording sensitivity is extremely high,
We have completed an image-receiving sheet that gives a recorded image of extremely high image quality that is extremely excellent in resolution, sharpness, color density, and dot dropout.

[0008]

The present invention provides a thermal transfer recording image-receiving sheet comprising a support and an image-receiving layer for receiving a transfer image from a color material transfer sheet, the space between the image-receiving layer and the support. An image-receiving sheet for thermal transfer recording, characterized in that an intermediate layer containing resin fine particles having a multi-layer structure of three or more layers having an internal air layer is provided.

[0009]

The resin fine particles used in the image-receiving sheet of the present invention and having a multilayer structure of three or more layers having an internal air layer are generally represented by a medium represented by water or the like, for example, a polyamide type or polyester type. Prepared by dispersing a condensation-type resin fine particle, a poly-addition type resin fine particle typified by polyurethane type or epoxy type, or an addition polymerization type resin fine particle typified by vinyl type, into the dispersion liquid. A vinyl-based monomer is added while controlling the dropping rate to carry out a polymerization reaction to prepare a dispersion liquid of resin fine particles having at least one layer of the above dispersion medium and having a multilayer structure of three or more layers, Then, it is manufactured by a method of substituting at least a part of the internal dispersion medium with an air layer in a drying step.

Specific examples of the monomer used for producing resin fine particles having a multilayer structure include, for example, styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 4-methoxystyrene, vinyl chloride. , Vinylidene chloride, ethylene, vinyl cyclohexane, methyl methacrylate, hexyl acrylate, vinyl acetate, acrylonitrile, and other vinyl-based monomers. Examples thereof include rubbers such as 1,3-butadiene, isoprene, and 2-chloro-1,3-butadiene. It is also possible to lower the melting point, softening point and glass transition point of resin fine particles by adding a system monomer, or to increase the melting point, softening point and glass transition point of resin fine particles by adding a crosslinking agent such as divinylbenzene. it can.

Further, in order to modify the surface characteristics of the resin fine particles, an α, β-ethylenically unsaturated carboxylic acid monomer such as acrylic acid, methacrylic acid, maleic acid, itaconic acid or fumaric acid is added, and It is also possible to modify the resin by polymerization or polymer reaction. As a specific example of the resin fine particles having a multilayer structure, for example, resin fine particles having a three-layer structure having an internal water layer are commercially available from Mitsui Toatsu Chemicals, Inc. under the trade name of Grosdale 1003-E. There is.

In the image-receiving sheet of the present invention, the thus-obtained resin fine particles having a multilayer structure are contained in the intermediate layer between the image-receiving layer and the support. At that time, the resin fine particles are freeze-dried, It can be taken out and used as a dry powder by a method such as spray drying, but in general, resin fine particles produced as an aqueous dispersion are blended as they are in a coating liquid for forming an intermediate layer, According to the above, the intermediate layer is formed by a method of coating and drying a coating liquid prepared by blending binders, auxiliaries and the like on a support. At this time, of course, two or more kinds of resin fine particles may be used together.

Examples of the binders include modified starch,
Natural or semi-synthetic polymers such as carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, casein, gelatin, natural rubber, polydiene such as polyvinyl alcohol, isoprene, neoprene and polybutadiene, polyalkene such as polybutene, polyisobutylene, polypropylene and polyethylene. , Vinyl halides, vinyl acetate, styrene, (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamide, methyl vinyl ether and other vinyl polymers and copolymers,
Examples include so-called coating binders such as polyesters, polyurethanes, polyamides, styrene / butadiene-based, methyl methacrylate / butadiene / maleic acid-based synthetic rubber latex, and other synthetic polymers. Among them, binders exhibiting thermoplasticity in the recording energy range are particularly preferably used.

The amount of the binders used is adjusted within a range that does not impair the working effects of the resin fine particles constituting the intermediate layer, but is generally 500% by weight or less, preferably 0.01 to 200% by weight of the resin fine particles. Used in a range of degrees. Examples of various auxiliaries include inorganic and organic pigments such as calcium carbonate, talc, kaolin, titanium oxide, aluminum hydroxide, zinc oxide, urea / formaldehyde resin particles, melamine resin particles, guanamine resin particles, and color tone. Further, dyes for controlling whiteness, ultraviolet absorbers and antioxidants for improving storability, dispersants for imparting smearability, wetting agents, defoaming agents and the like can be added.

In the image-receiving sheet of the present invention, if the thickness of the intermediate layer is less than 0.5 μm, the desired effect cannot be expected. Therefore, the thickness of the intermediate layer is 1 μm or more, preferably 2 to 50 μm. It is desirable to adjust within a range. Further, before or after forming the image receiving layer on the intermediate layer, if the smoothing treatment is performed by heating / pressurizing treatment with a super calender or a cast drum, the recording sensitivity of the image receiving sheet obtained can be further enhanced. ..
At that time, the average particle diameter of the resin fine particles constituting the intermediate layer,
If it is less than 0.1 μm, the effect of the smoothing treatment is hardly obtained, and if it exceeds 50 μm, not only the coating suitability but also the effect of the smoothing treatment cannot be expected. Therefore, adjusting the average particle diameter of the resin fine particles to the range of about 0.2 to 10 μm is one of the preferred embodiments of the present invention.

Regarding the image-receiving layer provided on the intermediate layer,
Although not particularly limited, generally, a thermoplastic resin layer having an effective dyeing ability for a sublimable dye is preferably used. Examples of the thermoplastic resin include polymers and copolymers of vinyl monomers such as styrene, vinyltoluene, acrylic acid ester, methacrylic acid ester, acrylonitrile, vinyl chloride and vinyl acetate, polyester,
Examples thereof include condensation polymers such as polyamide, polycarbonate, polysulfone, epoxy resin and polyurethane, and cellulose resins.

These thermoplastic resins may be used alone, or two or more kinds of resins having different properties may be used in combination. In addition, if necessary, other resin materials such as methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, starch, polyvinyl alcohol, polyamide resin, phenol resin, melamine resin, urea resin, urethane resin, epoxy resin, silicone resin, and fluororesin. May be contained, and it is also possible to modify the image receiving layer by adding a reactive compound such as a polyvalent isocyanate compound, an epoxy compound or an organometallic compound. However, it is necessary to keep the thermoplastic synthetic resin forming the image receiving layer within the range in which the thermoplasticity is not lost.

Further, for the purpose of improving the writing property, the image-receiving layer is, for example, heavy or light calcium carbonate, talc, clay, natural or synthetic silicic acid, titanium oxide, aluminum hydroxide, zinc oxide, urea formaldehyde resin. Inorganic or organic pigments such as powders, ultraviolet absorbers, antioxidants, antistatic agents, release agents, lubricants and various other auxiliaries can be added as appropriate.

The coating amount of the constituents forming the image-receiving layer on the intermediate layer is appropriately adjusted depending on the purpose of use of the image-receiving sheet, but generally it is ² to 15 g / m ^{2 in} dry weight. Coated to a degree. As the support, plain paper, synthetic paper, synthetic resin film, or the like can be used as appropriate, but plain paper is preferable because it has excellent thermal characteristics. In addition, the plain paper referred to here is, for example, a paper obtained by ordinary papermaking, containing cellulose pulp as a main component, a paper strengthening agent, a sizing agent, a fixing agent, an inorganic or organic filler, and the like, It also includes papers whose surface properties have been improved by size-pressing oxidized starch or the like or providing a precoat layer containing a pigment such as clay as a main component, but such as art paper, coated paper, cast coated paper, etc. In particular, paper having an excellent surface smoothness is particularly preferably used.

Before or after providing the intermediate layer, an anchor coat layer may be provided on these supports in order to control the adhesiveness, barrier property, smoothness, concealing property, etc., or a thin film substrate. It is also possible to laminate or laminate. Further, on the image receiving layer, for example, JP-A-59-165688 and JP-A-61-27.
As disclosed in Japanese Patent Publication No. 290, etc., a thin heat-resistant release layer containing a silicon resin having a property of transmitting a sublimation dye as a main component is formed, and a dye or a dye is transferred from a color material transfer sheet. It is also possible to prevent direct transfer of the layer.

The thus-obtained image-receiving sheet for thermal transfer recording of the present invention exhibits extremely excellent performance especially as an image-receiving sheet when a sheet containing a heat sublimable dye is used as a color material transfer sheet. It has excellent recording sensitivity and can provide a recorded image with high image quality, which is extremely excellent in resolution, definition, color density, dot dropout, and the like. The reason why such an excellent effect is obtained is not necessarily clear, but the special resin fine particles, which are a constituent component of the intermediate layer, exert their characteristics during thermal transfer recording, and the heat transfer from the recording head is uniform. It is presumed that this is for the purpose of improving the adhesion between the color material transfer sheet and the image receiving sheet as well as controlling.

The heat sublimable dye referred to in the present invention does not cause the color material to transfer even when it comes into contact with the image receiving sheet under normal handling conditions, but it is first melted and vaporized by heating at 60 ° C. or higher. , A dye that causes a transition of a coloring material due to sublimation, etc., for example, azo type, nitro type,
It is used by appropriately selecting from various dyes such as disperse dyes typified by anthraquinone type and quinoline type, basic dyes typified by triphenylmethane type, fluorane type and oil-soluble dyes.

Further, the image-receiving sheet for thermal transfer recording of the present invention is not limited to a thermal recording system of contact heating with a thermal plate such as a thermal printing unit or a thermal head, but also a heat ray such as an infrared lamp, a YAG laser or a carbon dioxide gas laser. It is also useful for thermal recording by a non-contact heating method using radiation.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.
Unless otherwise specified, "part" and "%" in the examples are
"Parts by weight" and "% by weight" are shown, respectively.

Example 1 Multi-layer structured resin fine particle dispersion liquid (trade name: Grosdale 1
003-E, average particle size 0.7 μm, solid content concentration 40
%, Manufactured by Mitsui Toatsu Chemicals, Inc., 800 parts, polyolefin resin fine particles (trade name: Chemipearl A-100, average particle size 5)
μm, solid content concentration 40%, manufactured by Mitsui Toatsu Chemicals, Inc. 100 parts, and styrene-butadiene copolymer emulsion (trade name: L-1690, solid content concentration 48) as a binder.
%, Manufactured by Asahi Kasei Co., Ltd.) and water was added to prepare a coating liquid for forming an intermediate layer having a solid content concentration of 40%. Commercially available double-sided art paper (trade name: SA-Kinfuji, basis weight 1
28 g / m ² , Kanzaki Paper Co., Ltd.) and dry weight of 15 g
/ M ² was applied and dried to form an intermediate layer. Then, 20 parts of a polyester resin (trade name: Byron 200, manufactured by Toyobo Co., Ltd.) is dissolved in 40 parts of methyl ethyl ketone, 40 parts of toluene, and 20 parts of cyclohexanone, and an amino-modified silicone oil (trade name: KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.). ) 0.3 part and an epoxy-modified silicone oil (trade name: X-33-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.3 part were added to prepare a coating liquid for forming an image receiving layer. This coating solution was applied onto the intermediate layer so that the dry weight was 4 g / m ^2, and 1
It was dried at 20 ° C. for 5 minutes and cured by heating. Next, a smoothing treatment (linear pressure of 200 kg / cm) was performed using a super calender consisting of a mirror-finished metal roll and an elastic roll to obtain an image-receiving sheet for thermal transfer recording.

Example 2 Multi-layered structure resin fine particle dispersion liquid (trade name: Grosdale 1
003-E) 300 parts, polyvinyl alcohol resin (trade name: Kuraray Poval PVA-10 as a binder
700 parts of a 10% aqueous solution of Kuraray Co., Ltd.) was mixed to prepare a coating liquid for forming an intermediate layer. An image receiving sheet for thermal transfer recording was obtained in the same manner as in Example 1 except that this intermediate layer forming coating liquid was used.

Comparative Example 1 In Example 1, instead of 800 parts of the multilayer structure resin fine particles (trade name: Grosdale 1003-E), porous urea resin fine particles (trade name: Eupearl C-122R,
Mitsui Toatsu Chemicals, Inc., nonvolatile content 22%, cake-like) 150
An image receiving sheet for thermal transfer recording was obtained in the same manner as in Example 1 except that 0 part was used.

Comparative Example 2 An image receiving sheet for thermal transfer recording was obtained in the same manner as in Example 1, except that the multilayer structured resin fine particles (trade name: Grosdale 1003-E) were not used.

The four types of image-receiving sheets for thermal transfer recording thus obtained were subjected to the following quality comparison tests, and the results are shown in Table 1. That is, 4 parts of blue heat sublimation dye (trade name: KST-B-714, manufactured by Nippon Kayaku Co., Ltd.), 4 parts of polyvinyl butyral resin (trade name: S-Rex BX-1, manufactured by Sekisui Chemical Co., Ltd.), and methyl ethyl ketone / Toluene (weight ratio 1
/ 1) Dissolved in 100 parts to prepare an ink for forming a color material layer. Then, a dry weight of 1 g of this ink was placed on a 6 μm-thick polyester film whose back surface was heat-treated.
It created a colorant transfer sheet by coating and drying so that / m ^2.

Next, the coating surfaces of the color material transfer sheet and the image receiving sheet for thermal transfer recording are superposed on each other, and heat is applied from the back surface of the color material transfer sheet by a thermal head (12 V, 4 to 16 m).
s), and a thermal transfer recording image was formed on the image receiving layer surface of the image receiving sheet. Then, the recording density and the image quality of each image receiving sheet and the recorded image were evaluated by the following methods.

[Evaluation Method] (Recording Density) Using a Macbeth densitometer (RD-914), the recording density was measured at five points with an applied pulse width of 4, 7, 10, 13, 16 ms. (Image quality) The image in the highlight part (7 ms) is observed with a 25X magnifying glass to visually judge dot reproducibility and dot omission,
Each was evaluated based on the following evaluation criteria. (Evaluation Criteria) A: No dot omission and good dot reproducibility. B: Some missing dots are observed, but there is no practical problem. C: Dot omission is conspicuous and there is a problem in practicality. D: Dot loss and reproducibility are poor, and practicality is completely absent.

[0032]

[Table 1]

[0033]

As is clear from the results shown in Table 1, the image-receiving sheets for thermal transfer recording obtained in the examples of the present invention have excellent recording sensitivity and can provide recorded images with extremely sharp and high color density. Not only that, but the image quality was also very good.

Claims (1)

[Claims] 1. An image-receiving sheet for thermal transfer recording comprising an image-receiving layer for receiving a transfer image from a color material transfer sheet on a support, wherein an internal air layer is provided between the image-receiving layer and the support. An image-receiving sheet for thermal transfer recording, comprising an intermediate layer containing fine resin particles having a multilayer structure of at least one layer.