JP2826111B2 - Sublimation type thermal transfer recording medium - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sublimation type thermal transfer recording medium.

2. Description of the Related Art In recent years, the demand for full-color printers has been increasing year by year, and the recording methods of the full-color printer include an electrophotographic method, an ink-jet method, and a thermal transfer method. Among them, thermal transfer is easy due to easy maintenance and no noise. Many methods are used.

This thermal transfer consists of a solidified color ink sheet and an image receiving paper, and heat transfer or sublimation transfer of the ink to the receiving paper by thermal energy controlled by an electric signal of a laser, a thermal head, etc., to form an image. This is a recording method to be performed.

The thermal transfer recording system is roughly classified into the heat melting transfer type and the sublimation transfer type. In particular, in the latter case, the sublimation dye sublimates in a monomolecular state corresponding to heat energy from a thermal head or the like in principle. It has the advantage that halftones can be easily obtained and the gradation can be controlled arbitrarily, and is considered to be the most suitable method for a full-color printer.

However, in this sublimation transfer recording method, a color ink sheet is used as a recording supply, and heat recording is selectively performed according to an image signal. In order to obtain one full-color image, yellow, magenta, cyan, (black) (1) Ink sheet is used one by one, and even if there is an unused portion, it is discarded.

Therefore, focusing on this drawback, the ink sheet and the image receiving body are moved at a constant speed in order to improve the drawback by using the ink sheet a number of times, and the constant speed mode method used repeatedly and the running speed of the ink sheet are used. An N-fold mode method has been proposed in which the overlap of the first use portion and the second use portion of the color material layer is gradually shifted and used later than that of the image receiving body.

However, in the sublimation type thermal transfer recording system, sublimation and evaporation reactions are basically zero-order reactions, and in the constant velocity mode, although the amount of dye that can withstand multi-use is included in the ink layer, As the number of prints increases, the transfer density particularly in the high image density area rapidly decreases,
Many times of printing could not be performed substantially.

In view of this, the present inventors have proposed in Japanese Patent Application No. 63-62866 a sublimation-type thermal transfer recording medium having a laminated structure, and referred to as "Dye supply capability between a dye supply layer and a dye transfer contributing layer. Layer> Dye transfer contributing layer "improved density reduction in multiple recordings.

However, in the recording medium, as described later, in theory, the dye supply layer generally has a low binder resin content in order to increase the dye concentration or increase the diffusion coefficient,
If the adhesion to the support deteriorates and the recording conditions are different (for example, when the applied voltage increases, the receiving layer changes), the entire ink layer is transferred to the image receiving side (so-called ink layer peeling), and the image quality is reduced. There was a problem that impaired.

Further, as described above, when recording is performed a large number of times by the N-times mode method, there is a risk that the dye transfer contributing layer and the surface of the image receiving member are more closely adhered or frictioned to each other, resulting in poor running.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sublimation type thermal transfer recording medium which does not cause a rapid decrease in transfer density even when the number of printings is increased, does not cause peeling and fusing of an ink layer, and prevents running defects.

Structure The present invention provides a sublimation-type thermal transfer obtained by laminating a dye supply layer, a dye transfer contributing layer, and a release thin layer in which a sublimable dye is dispersed in an organic binder in order from the substrate side. In a recording medium, the dye supply layer contains at least an undissolved particulate sublimable dye, and the dye transfer contributing layer contains at least a molecularly dispersed sublimable dye. Medium.

The present inventors have acceptance and dye transfer contribution layer 5 in the bonding force F ₁ and the ink layer 2 between the support 1 and the first figure as shown, the dye-supplying layer 4 in the ink layer 2 Support 7 as body
Relationship between the adhesive force F ₂ between the receiving layer 3 of the above, conventionally F ₁ <
Considered which was a F _2, in the present invention was made to be F _1> F ₂ by reducing the value of F _2. By laminating thin release layer formed of a material having a lubricating property and heat resistance in dye transfer contribution layer in the present invention in order to maintain the relationship of such balance, to reduce the F _2, the intended present invention You have achieved your goal.

Examples of the substance having lubricity and heat resistance used for forming the release layer include the following (A) curable silicone. As long as the silicone is a curable type, it may be a one-part type or a two-part type. Although the curable silicone layer is a thin layer, it has sufficient release properties and heat resistance, and also has sufficient transparency of the sublimated coloring material.

On the other hand, a mixture of (B) a substance having lubricity or thermal releasability (lubricating substance) described below and (C) a heat-resistant resin may also be used.

Further, it may contain an inorganic powder such as silica, TiO ₂ and calcium carbonate, and an organic powder such as silicone and cellulose, as appropriate.

The thickness of the release thin layer is 2μ or less, preferably 0.05μ ~
The reason is that 1 μ is appropriate, because if the release layer is too thick, the sublimed color material is hardly transmitted, and if a normal transfer density is to be obtained, high recording energy is required. There is no peeling effect and there is a risk of fusing.

(A) Curable Silicone The silicone resin has the following structure.

(However, in the above formula, R and R ₁ represent a methyl group, a phenyl group, and the like.) Various modified silicone resins such as an alkyd-modified silicone resin, an epoxy-modified silicone resin, and an acryl-modified silicone resin can also be used. . Conversely, silicone-modified acrylic resin obtained by modifying silicone,
A silicone-modified acrylic urethane resin or the like can also be used. Needless to say, the above resin is preferably obtained by blending a curing agent or a crosslinking agent and curing or crosslinking.

(B) Substances having lubricating or releasing properties (lubricating substances) For example, synthetic lubricating oils such as petroleum lubricating oils such as liquid paraffin, hydrogen halides, diester oils, silicone oils, fluorosilicone oils, and various modified silicone oils (Epoxy-modified, amino-modified, alkyl-modified, polyether-modified, etc.), silicone-based lubricating substances such as copolymers of organic compounds such as polyoxyalkylene glycol and silicone,
Various fluorine-based surfactants such as fluoroalkyl compounds, fluorine-based lubricating substances such as ethylene trifluoride-chlorinated ethylene low polymer,
There are waxes such as paraffin wax and polyethylene wax, higher fatty acids, higher fatty acid alcohols, higher fatty acid amides, higher fatty acid esters, higher fatty acid salts, and various kinds of particles mentioned as the above-mentioned particles having lubricity or heat release properties. .

(C) Heat resistant resin Any resin having heat resistance may be used.
The resin is not particularly limited as long as it is a resin having a temperature of 100 ° C. or higher and a melting point or softening point of 200 ° C. or higher. For example, epoxy resin, silicone resin, xylene resin, urea resin, melamine resin, unsaturated polyester resin, alkyd resin,
Examples thereof include thermosetting resins such as furan resins, and thermoplastic resins such as cellulose acetate, cellulose butyrate acetate, polysulfone, polycarbonate, polystyrene, and acrylic resins that exhibit relatively high heat resistance. Each of them may be blended with a curing agent or a cross-linking agent, and cured by heat or ultraviolet. The dye supply layer and the dye transfer contributing layer were each formed as a single layer on the substrate with the same amount of adhesion in each of the formulations, each was superimposed on a separate image receiving layer, and the same thermal energy was applied to both. At this time, the amount of dye transferred to each image receiving layer is in the relationship of dye supply layer> dye transfer contributing layer.

The thermal transfer may be performed by a thermal head. Alternatively, the support layer and / or the ink layer may be adjusted to generate Joule heat by energization, and may be performed by energization transfer.

Alternatively, a laser transfer method can be used by selecting a material that absorbs laser light and generates heat as the support.

According to the knowledge of the present invention, the diffusion of the dye in the ink layer is Fick's law, that is, the amount of the dye dn that has passed through the cross-sectional area q at the dt time is represented by the dye concentration gradient dc in the diffusion direction.
Assuming that / dx is the average diffusion coefficient of each part in the ink layer when heat is applied, the relationship of dn = − (dc / dx) qdt is applied.

Therefore, as means for facilitating the diffusion and supply of the sublimable dye from the dye supply layer to the transfer contributing layer, there are: I. a relation of the dye supply layer> the transfer contributing layer with respect to the dye concentration, and / or II. There is a means for making the relationship of the dye supply layer> the transfer contributing layer related to the diffusion coefficient in the layer. Further, as a specific method of operating the diffusion coefficient with respect to the above II, for example, Toyoko Sakai et al.
o.12 (1974); Norihiko Kuroki, Dyeing Theory Chemistry, published by Maki Shoten
p.503-; introduced in the 1st Non-Impact Printing Technology Symposium Paper Collection 3-5. With reference to these, specific methods for realizing the above-mentioned means II include, for example, (1) Since the diffusion coefficient is affected by the energy suppression effect on dye diffusion due to hydrogen bonding between the dye and the organic binder, etc. A method of using an organic polymer material having a large number of proton-supplying groups or proton-accepting groups which are easily hydrogen-bonded to a sublimable dye as a binder of the transfer-contributing layer. (2) The diffusion coefficient is determined by dispersing the dye. Since the organic binder has a glass transition or softening temperature dependency, the diffusion coefficient is higher when the glass transition or softening temperature is lower than the temperature rise characteristics of the layer during printing in this process, and therefore, the organic binder in the dye supply layer is higher. (3) using a substance having a lower glass transition temperature or a lower softening temperature than that of the transfer contributing layer as a binder, (3) having a compatibility with at least one organic binder in the dye supply layer, and A method in which a plasticizer which is incompatible with all the organic binders in the layer is contained in the dye supply layer; (4) a method in which the above methods (1), (2) and (3) are appropriately combined. There are methods and the like, but it is needless to say that the method is not limited to these methods as long as the above relationship of the diffusion coefficient is satisfied.

In designing the material formulation of the dye supply layer and the transfer contributing layer in the present invention, the above-mentioned I and / or II are useful means, and a simple method for confirming whether or not the intended improvement is realized by these effects. As a simple method, when the same amount of coating is formed as a single layer on a substrate in each of the prescriptions of the dye supply layer and the transfer contributing layer, each is superimposed on a separate image receiving layer, and when a certain sublimation temperature is applied, sublimation occurs. There is a method of selecting each layer such that the transfer amount satisfies the relationship of the dye supply layer> the transfer contributing layer.

Next, the thickness of the transfer contributing layer is generally 0.05 to 5 μm,
Preferably, it is 0.1 to 2 μm. The thickness of the dye supply layer is generally 0.1 to 20 μm, preferably 0.5 to 10 μm.

Known sublimable dyes, binders and the like used in the transfer contributing layer and the dye supply layer of the present invention can be used.

The sublimable dye is a dye that sublimates or vaporizes at 60 ° C. or higher, and may be any of those mainly used in thermal transfer printing such as disperse dyes and oil-soluble dyes.For example, CI Disperse Yellow 1,3,8, CI Disperse Blue 3,14,19, such as 9,16,41,54,60,77,116, CI Disperse Red 1,4,6,11,15,17,55,59,60,73,83 , 26,56,60,64,7
2,99,108, CI Solvent Yellow 77,116, etc.
CI Solvent Red 23, 25, 27 and CI Solvent Blue 36, 83, 105 and the like can be mentioned. One of these dyes can be used, but several kinds of dyes can be used.

Thermoplastic or thermosetting resin is used for the binder used for the dye transfer contributing layer and the dye supply layer. Among the resins having a relatively high glass transition point or high softening property, for example, vinyl chloride resin , Vinyl acetate resin, polyamide, polyethylene, polycarbonate, polystyrene, polypropylene, acrylic resin, phenol resin,
Polyester, polyurethane, epoxy resin, silicone resin, fluorine resin, butyral resin, melamine resin,
Examples include natural rubber, synthetic rubber, polyvinyl alcohol, and cellulose resin. These resins can be used singly, but a mixture of several resins or a copolymer may be used.

Further, when making a difference with respect to the glass transition or softening temperature between the dye transfer contributing layer and the dye supply layer, a resin or a natural or synthetic rubber having a glass transition temperature of 0 ° C. or less, or a softening temperature of 60 ° C. or less is preferable. Include syndiotactic 1,2-polybutadiene (commercially available as JSR RB810,820,830 Nippon Synthetic Rubber); olefin copolymers and terpolymers containing acids or non-acidic acids (commercially available as Dexon XEA-7, Dexon Chemical); Ethylene-vinyl acetate copolymer (400 & 400A, 405,43 as a commercial product)
0, Allied Fibers &Plastics; P-3307
(EV150), P-2807 (EV250), Dupont Mitsui Polychemicals; low molecular weight polyolefin polyols and their derivatives (Polytail H, HE Mitsubishi Kasei Kogyo as commercial products); brominated epoxy resin (YDB-340,400,500,600 Toto Kagaku) Novolak type epoxy resin (YDCN-701,702,70)
3 Toto Chemical); Thermoplastic acrylic solution (Tynalnal LR1075,1080,1081,1082,1063,1079 Mitsubishi Rayon); Thermoplastic acrylic emulsion (LX-400, LX-45)
0, Mitsubishi Rayon); polyethylene oxide (Alcox E-30,45, Alcox R-150,400,1000 Meisei Chemical); caprolactone polyol (Placcel H-1,
And the like. In particular, polyethylene oxide and polycaprolactone polyol are practically useful, and the above-mentioned thermoplastic or thermosetting resin is mixed with one or more of the above-mentioned thermoplastic or thermosetting resins. It is preferred to use it in form.

The dye concentration of the transfer contributing layer is usually 5 to 80%, preferably,
It is about 10-60%.

The dye concentration of the dye supply layer is preferably from 5 to 80%. However, when a dye concentration gradient is provided between the dye transfer contribution layer and the dye supply layer, the dye concentration is 1.1 to 1.1%. ５5 times, preferably 1.5 to 3 times.

The dye supply layer contains at least an undissolved particulate sublimable dye in order to stably supply the dye for a long time and maintain good printing characteristics. Here, the undissolved particulate dye refers to the ink (organic binder + sublimable dye +
(Solvent) after application and drying, meaning a dye that cannot be completely dissolved in the organic binder and precipitates as particles. The presence of the undissolved particulate dye differs depending on the solvent even with the same binder and dye. The presence or absence of the undissolved particulate dye can be easily identified by an electron microscope after forming the dye supply layer. Although the particle size of the undissolved particulate dye varies depending on the thickness of the dye supply layer, it is 0.01 μm to 20 μm.
μm, preferably 1.0 μm to 5 μm.

Further, the dye state in the dye transfer contributing layer is that it is dispersed in a monomolecular state which actually contributes to the transfer, preventing the occurrence of uneven transfer density and the dye between the dye supply layer and the dye transfer contributing layer. Keep the concentration gradient stable.

As the base sheet, a film such as a condenser paper, a polyester film, a polystyrene film, a polysulfone film, a polyimide film, or a polyamide film is used. Between the base sheet and the dye supply layer, if necessary, a conventional adhesive layer is used. A conventional heat-resistant lubricating layer may be provided on the back surface of the base sheet, if necessary.

The plasticizer contained in the dye supply layer referred to in the above method (3) refers to a plasticizer that enters between the molecules of the resin, weakens van der Waals bonds that cause the rigid network structure of the resin, and consequently causes the secondary A substance which lowers the transition point and is soluble is defined as a substance in which a resin and a plasticizer have an affinity for each other, have a high gelation rate, and do not separate the plasticizer even after molding.

Also, specifically, considering the compatibility between the plasticizer and the resin, books, references, catalogs, etc., which mention the plasticizer, such as Sakura Yamada, “Plastic Compounding Agent” (published by Taiseisha, p.17 −) And “9887 Chemical Products” (published by The Chemical Daily, p. 745-).

For example, combinations shown in the following table are given.

In these combinations, the plasticizer and the compatible resin are used for the dye supply layer, and the incompatible resin is used for the transfer contributing layer.
As the preferred plasticizer, those described in the above table which are excellent in heat resistance and volatility are preferable, and the compounding ratio of the plasticizer to the resin is 10 to 100%, preferably 10 to 50%.

So far, an example in which the dye layer is divided into two layers has been described. However, if an appropriate difference in dye transfer amount is generated and the function separation intended by the present invention can be achieved, the dye layer may be formed into a multilayer of two or more layers. It is possible.

Although the above description has been made with reference to a recording method using a thermal head, the transfer medium of the present invention is a recording method in which recording heat energy is applied by a method other than the thermal head, for example, a thermal printing plate, a laser beam, or a support. It can also be used for a method using Joule heat generated in a medium such as a body. Of these, the so-called energetic thermal transfer method using Joule heat generated in a medium is best known, for example, USP
4,103,066, JP-A-57-14060, JP-A-57-11080, or JP-A-59-9906.

When used in this energization transfer method, relatively heat-resistant polyester, polycarbonate, triacetyl cellulose, nylon, polyimide, aromatic polyamide and other resins as a support, aluminum, copper, iron, tin, zinc,
Metal powders such as nickel, molybdenum, silver and / or conductive powders such as carbon black are dispersed to adjust the resistance to an intermediate value between the insulator and the good conductor. A support on which a conductive metal is deposited or sputtered may be used. The thickness of these supports is preferably about 2 to 15 microns in consideration of the efficiency of Joule heat conduction.

In the case of using a laser beam transfer method, a material that absorbs laser light and generates heat may be selected as a support.
For example, a conventional heat transfer film containing a light-absorbing heat exchange material such as carbon, or a film having an absorption layer formed on the front and back surfaces of a support is used.

Hereinafter, the present invention will be described more specifically based on the following examples, but the present invention is not limited thereto.

Example 1 Parts by weight Polyvinyl butyral resin BX-110 (manufactured by Sekisui Chemical Co., Ltd.) Sublimable dye KAYASET BLUE 714 (manufactured by Nippon Kayaku Co., Ltd.) Solvent Toluene 100 Methyl ethyl ketone 100 In the above formulation, for the dye supply layer The formulation was 20 parts by weight of the above-mentioned sublimable dye, and the formulation for the dye transfer contributing layer was 10 parts by weight of the above-mentioned sublimable dye. Each composition was dispersed in a ball mill for 24 hours.

Next, a sublimation type thermal transfer medium having a structure as shown in FIG. 1 was prepared as follows.

8.5μm polyimide film (Toray Dupont Co., Ltd.)
Is used as a support 1, and the ink for the dye supply layer 4 in the ink layer 2 is coated on the support 1 with a wire bar.
After applying 2.40 μm, further apply 0.61 μm of the ink for dye transfer contributing layer 5 in the ink layer 2 on the ink layer 2, and after drying,
A mixed solution of the following formulation was applied thereon as a release thin layer to a thickness of 0.5 μm using a wire bar, and dried at 100 ° C. for 1 minute to form a sublimation type thermal transfer medium.

Parts by weight Silicone resin: KS-772 10 (manufactured by Shin-Etsu Chemical) Curing agent: CAT-PL-3 0.5 Solvent: toluene 100 Example 2 The formation up to the dye transfer contributing layer is exactly the same as in Example 1, and A mixture of the following formulation was applied as a release thin layer to a thickness of about 0.5 μm using a wire bar.
After drying for 40 minutes, the resultant was dried at 40 ° C. for 2 days to form a sublimation type thermal transfer medium.

Parts by weight Polyvinyl butyral resin: BX-110 (manufactured by Sekisui Chemical Co., Ltd.) Diisocyanate: Takenate D-110N 1 (Takeda Chemical) Silicone oil: KF-858 1 (manufactured by Shin-Etsu Chemical) Solvent: toluene 95 methyl ethyl ketone 95 3. The formation up to the dye transfer contributing layer is exactly the same as in Example 1, and a mixed solution of the following formulation is applied thereon as a release thin layer to a thickness of about 0.5 μm using a wire bar, At 1
After drying for 40 minutes, it was left to dry at 40 ° C. for 2 days to form a sublimation type thermal transfer medium.

Parts by weight Silicone resin liquid: SD7223 30 (solid content: 30%, made by Toray Silicone) Curing agent: SRX-212 0.27 (made by Toray Silicone) Silica 2.5 Solvent: toluene 70 n-hexane 30 Example 4 Formation up to Dye Transfer Contributing Layer Is exactly the same as in Example 1, and a UV-curable silicone KNS-5002 (manufactured by Shin-Etsu Chemical Co., Ltd.) is applied thereon as a release layer, and then the UV-curing device (UV 20 W / cm × 8 lamps) is used. Ultraviolet irradiation was performed for 5 minutes to form a 0.3 μm release layer, thereby forming a sublimation type thermal transfer medium.

Example 5 The formation up to the dye transfer contributing layer is exactly the same as in Example 1, and a mixed solution having the following formulation is applied thereon as a release thin layer using a wire bar to a thickness of about 0.5 μm. After drying at 80 ° C. for 1 minute, the substrate was dried at 40 ° C. for 2 days to form a sublimation type thermal transfer medium.

Parts by weight Silicone-modified acrylic urethane resin liquid: UA-53F30 (solid content: 44%, manufactured by Sanyo Chemical Industries) Hardener: L2-2KO14A (manufactured by Sanyo Chemical Industries) 1 Solvent: Methyl ethyl ketone For sublimation transfer recording media of 100 or more As the image receiving medium, a mixture prepared by applying a mixed solution having the following formulation onto a synthetic paper having a thickness of 150 μm with a wire bar and providing a receiving layer of about 5 μm was used.

Parts by weight Polyester resin Byron 200 10 (manufactured by Toyobo Co., Ltd.) Silicone oil SF8417 1 (manufactured by Toray Silicone) Toluene 50 Methyl ethyl ketone 50 As shown in FIG. 1, printing conditions using the thermal head 6 on the receiving layer 3 As applied power 442mW / dot,
FIG. 2 shows the result of performing printing many times at the same location at the maximum applied energy of 2.21 mJ / dot. However, the print density (optical density) was evaluated using a Macbeth densitometer RD-514. FIG. 2 shows the relationship between the number of prints and the saturated image density. In the thermal transfer recording media of Examples 1 to 5, even when the number of prints was increased to seven, the image density was substantially the same as that of the first print. Did not differ. As described above, it was found that the thermal transfer recording medium of the present invention had good multi-time printing characteristics without a decrease in print density even when printing was performed many times. On the other hand, as a result of visually observing the peeling of the ink layer (so-called abnormal transfer of the ink layer to the image receiving body side), no abnormal transfer image or running failure due to the peeling was observed.

Reference Comparative Example 1 A sublimation-type thermal transfer medium was formed in the same manner as in Example 1 except that the sublimable dye was used in an amount of 13.3 parts by weight in the formulation for the dye supply layer in Example 1, and printing was performed many times under the same conditions. . The image density is
It decreased as the number of printings increased from the first time. The results are shown in FIG.

REFERENCE COMPARATIVE EXAMPLE 2 The dye supply layer formulation of Example 1 was changed to 13.3 parts by weight of a sublimable dye, and the dye transfer contributing layer was formulated by a water-soluble saturated polyester resin (Nippon Synthetic Chemical Co., Ltd., Polyester WR901).
Sublimation type thermal transfer medium was formed in the same manner as in Example 1 except that the parts by weight, polyvinyl alcohol (Gosenol KH-17, Nippon Synthetic Chemical Co., Ltd.) and water were changed to 1 part by weight, and printing was performed many times under the same conditions as in Example 1. Was done. The results are shown in FIG. The image density increased from the first time to the third time, and then decreased as the number of printings increased.

Effect As described above, the sublimation-type thermal transfer body of the present invention in which the ink layer configuration is improved, the print density does not substantially decrease even when printing is performed a large number of times, and has good multiple printing characteristics, It does not cause delamination and fusion, and prevents running defects.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the structure of a sublimation type thermal transfer body of the present invention. FIG. 2 is a graph showing the relationship between the saturated print density of the sublimation type thermal transfer body of the present invention and the number of times of printing. FIG. 3 is a graph showing the relationship between the saturated print density and the number of prints of the sublimation type thermal transfer bodies of Reference Comparative Examples 1 and 2. 1,7 ... Support, 2 ... Ink layer 3 ... Receiving layer, 4 ... Dye supply layer 5 ... Transfer contributing layer, 6 ... Thermal head

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroyuki Uemura 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-2-2077 (JP, A) JP-A-Hei 1-263084 (JP, A) JP-A-2-586 (JP, A) JP-A-2-25389 (JP, A) JP-A-63-47193 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41M 5/38-5/40

Claims (1)

(57) [Claims] 1. A sublimation type thermal transfer comprising a dye supply layer formed by dispersing a sublimable dye in an organic binder, a dye transfer contributing layer, and a release thin layer on a substrate in order from the substrate side. In a recording medium, the dye supply layer contains at least an undissolved particulate sublimable dye, and the dye transfer contributing layer contains at least a molecularly dispersed sublimable dye. Medium.