JP3287611B2 - Thermal transfer image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer image forming method, and more particularly to a thermal transfer image forming method using a dye transfer sheet and a dye receiving sheet.

[0002]

2. Description of the Related Art Conventionally, various thermal transfer image forming methods are known. Among them, a dye layer containing a sublimable dye is supported on a base sheet such as paper or a plastic film to form a dye transfer sheet. There have been proposed methods of forming various full-color images on a transfer medium such as paper or plastic provided with a dye receiving layer. In this case, a thermal head of a printer is used as a heating means, and a large number of three or four color dots are transferred to a transfer target by heating for a very short time, and a full-color image of a document is formed by the multicolor dots. That is to reproduce.

[0003] The image formed in this way is very clear and excellent in transparency because the coloring agent used is a dye, so that the resulting image has an intermediate color reproducibility and gradation. It is possible to form a high-quality image which is similar to an image obtained by conventional offset printing or gravure printing, and is comparable to a full-color photographic image.

Further, in order to prevent the image quality from being affected by the surface irregularities and texture of the transfer receiving member, first, a dye image is formed on a receiving layer of a dye receiving sheet provided with a releasable receiving layer. Thereafter, a method has been proposed in which a dye image-receiving sheet is heated to transfer a receptor layer on which an image is formed onto a transfer-receiving member.

[0005]

However, in the thermal transfer image forming method for forming an image on a transfer member provided with a dye receiving layer, a large dye transfer sheet such as A4 to A3 size is used. There is a problem that wrinkles are generated on the dye transfer sheet due to heat and mechanical stress in the printer, and image quality is deteriorated. Further, in order to solve such a problem, it is necessary to adjust the stress distribution of the transport mechanism of the printer, which makes the management complicated, and the use of an expensive heat-resistant resin sheet as a base sheet of the dye transfer sheet makes it possible to use the dye. There is a problem that the cost of the transfer sheet increases.

In a thermal transfer image forming method in which a dye image is once formed on a receiving layer of a dye image-receiving sheet, and then the receiving layer on which the image is formed is transferred onto a transfer-receiving member, a heating direction during image formation is used. (Heating from the dye transfer sheet side) and the heating direction during transfer of the receiving layer (heating from the dye image receiving sheet side) are opposite, so either two thermal heads or one thermal head and other heating means (stamper) , A line heater, a heating roll, a heating platen roll, etc.). Therefore, there is a problem that an inline printer having a complicated structure or offline processing is required.

The present invention has been made in view of the above circumstances, and provides a thermal transfer image forming method capable of simplifying the structure of a thermal transfer device, forming an image with high wear resistance, and reducing costs. The purpose is to do.

[0008]

The present invention provides a dye transfer sheet having a base sheet and a dye layer formed on one side of the base sheet, and a dye transfer sheet formed on the base sheet and one side of the base sheet so as to be peelable. A dye image-receiving sheet having a dye-receiving layer is overlapped so that the dye layer and the dye-receiving layer are in contact with each other, and from the base sheet side of the dye image-receiving sheet.
An image is formed on the dye receiving layer by applying thermal energy with a thermal head , and then the thermal image forming apparatus is used for forming the image from the base sheet side of the dye image receiving sheet.
The transfer of the dye-receiving layer to a transfer-receiving member is performed by applying heat energy again with a head.

[0010]

The dye is transferred from the dye layer of the dye transfer sheet onto the dye receiving layer of the dye image receiving sheet by the heat energy applied from the base sheet side of the dye image receiving sheet to form an image.

Further, the dye is transferred from the dye layer of the dye transfer sheet to the dye receiving layer releasably provided on the dye image receiving sheet by thermal energy applied from the base sheet side of the dye image receiving sheet. Is formed, and thereafter, heat energy is applied again from the base sheet side of the dye image-receiving sheet, whereby the dye-receiving layer on which the image has been formed is transferred to the transfer-receiving member.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The thermal transfer image forming method of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing an example of the thermal transfer image forming method of the present invention. In FIG. 1, a dye transfer sheet 11 includes a base sheet 12 and the base sheet 1.
The dye image receiving sheet 21 includes a base sheet 22 and a dye receiving layer 23 formed on one side of the base sheet 22. The dye transfer sheet 11 is pressed in the direction of the dye receiving sheet 21 by the platen roller 41 from the base sheet 12 side,
The dye transfer sheet 11 and the dye image receiving sheet 21 are overlapped so that the dye layer 13 and the dye receiving layer 23 are in contact with each other. Then, the base sheet 22 of the dye image receiving sheet 21
A thermal head 51 is in contact with the side, and the thermal head 51 is disposed at a position facing the platen roller 41.

As described above, in the present invention, thermal energy is applied from the base sheet 22 side of the dye image receiving sheet 21 by the thermal head 51, and the thermal energy causes the dye to be transferred from the dye layer 13 of the dye transfer sheet 11 to the dye image receiving sheet. The image is transferred onto the dye receiving layer 23 to form an image.

Examples of the dye transfer sheet 11 that can be used in the thermal transfer image forming method of the present invention include various known dye transfer sheets. Specifically, as the base sheet 12 of the dye transfer sheet 11, polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyvinyl chloride, polystyrene, nylon, polyimide, polyvinylidene chloride, polyvinyl alcohol, fluorine resin, Examples include plastic films such as chlorinated rubber and ionomer, papers such as condenser paper and paraffin paper, and nonwoven fabrics, and composites thereof.

In the present invention, since heat energy is applied from the base material sheet 22 side of the dye image receiving sheet 21 as described above, the base material sheet 12 has a high heat resistance unlike the base material sheet of the conventional dye transfer sheet. However, when the dye transfer sheet has versatility, the thickness of the base sheet 12 can be appropriately determined in consideration of the required strength, thermal conductivity, and the like. About 10 μm is preferable.

The dye layer 13 of the base sheet 12 is a layer in which a dye is supported by an optional binder resin. Examples of the dye to be used include those used in conventionally known dye transfer sheets. Specifically, as red dyes, MS Red G, Macrolex Red Violet R, Ceres
Red 7B, Samaron Red HBSL, Resolin Red F3BS, etc., and as the yellow dye, Holon Brilliant Yellow 6GL, PTY-52, Macrolex Yellow 6G, etc., and as the blue dye, Kayaset Blue 714,
Waxolin Blue AP-FW, Holon Brilliant Blue S-
R, MS Blue 100 and the like.

Examples of the binder resin for supporting the above-mentioned dye include ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and the like.
Cellulose-based resins such as methylcellulose, cellulose acetate, cellulose acetate butyrate, etc .; vinyl-based resins such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, and polyacrylamide; and polyesters. Among the above resins, cellulose-based, acetal-based, butyral-based, and polyester-based resins are preferred from the viewpoints of heat resistance, dye migration, and the like.

The dye layer 13 may contain various additives as necessary. And the dye layer 13
Has a thickness of 0.2 to 5 μm, preferably about 0.4 to 2 μm, and the dye layer 13 contains a sublimable dye in a proportion of 5 to 90% by weight, preferably 10 to 70% by weight. Is preferred.

On the other hand, as the base sheet 22 of the dye image receiving sheet 21 used in the thermal transfer image forming method of the present invention, those similar to the various sheets mentioned above as the base sheet 12 of the dye transfer sheet 11 are used. In particular, polyester resin sheets having high heat resistance such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ether ketone, and polyether sulfone are preferred. The thickness of the base sheet 22 of the dye receiving sheet 21 is
The strength, heat resistance and the like can be appropriately determined depending on the material so as to be appropriate, and usually about 1 to 10 μm is preferable.

As described above, in the present invention, thermal energy is applied from the side of the base sheet 22 of the dye receiving sheet 21 by the thermal head 51, so that the back surface layer May be formed. The back layer imparts heat resistance and slip properties to the base sheet 22, and includes a binder resin, a lubricant,
And other necessary additives.

As the binder resin used for the back layer,
For example, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose resin such as nitrified cotton, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, acrylic resin, polyacrylamide, acrylonitrile -Vinyl resins such as styrene copolymers, polyester resins, polyurethane resins, silicone-modified or fluorine-modified urethane, and the like. Among them, for example, it is preferable to use a binder resin having a reactive group such as a hydroxyl group, and to use a polyisocyanate or the like as a crosslinking agent in combination to form a crosslinked resin layer.

Examples of the lubricant used in the back layer include waxes such as polyethylene wax and paraffin wax, higher aliphatic alcohols, organopolysiloxanes, anionic surfactants, cationic surfactants, amphoteric surfactants, and the like. Nonionic surfactants, fluorine surfactants, organic carboxylic acids and derivatives thereof, and the like can be given. The amount of the lubricant contained in the back layer is 5 to 50% by weight,
Preferably, it is about 10 to 30% by weight.

The dye receiving layer 23 of the dye receiving sheet 21 is
This is for receiving the sublimable dye migrating from the dye layer 13 of the dye transfer sheet 11 and maintaining the formed image. Examples of the resin for forming the dye receiving layer 23 include polyolefin resins such as polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, vinyl polymers such as polyvinyl acetate and polyacrylester, and polyethylene. Terephthalate,
Polyester resin such as polybutylene terephthalate,
Polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, ionomers, cellulose resins such as cellulose diacetate, polycarbonate and the like,
Particularly, vinyl resins and polyester resins are preferable.

The dye receiving layer 23 preferably contains a release agent together with the above resin in order to prevent the dye transfer sheet 11 from being fused to the dye layer 13. Examples of the release agent to be used include silicone oil, phosphate ester-based surfactant, fluorine-based surfactant and the like, and silicone oil is particularly preferred. As the silicone oil, a modified silicone oil such as an epoxy-modified, an alkyl-modified, an amino-modified, a carboxyl-modified, an alcohol-modified, a fluorine-modified, an alkyl aralkyl-polyether-modified, an epoxy / polyether-modified, or a polyether-modified is preferable.

One or two kinds of the above-mentioned release agents are used.
The range of 0.5 to 30 parts by weight relative to 00 parts by weight is preferred. In the present invention, thermal energy is applied by the thermal head 51 from the base sheet 22 side of the dye receiving sheet 21 as described above, and the thermal energy causes the dye from the dye layer 13 of the dye transfer sheet 11 to be transferred to the dye of the dye receiving sheet 21. The image is transferred onto the receiving layer 23 to form an image. As a result, the dye receiving layer 23 of the dye image receiving sheet 21 is heated in advance just before the dye transfer, so that the dye receiving property of the dye receiving layer 23 is improved, and the formed image has high abrasion resistance. Becomes Further, in the dye image receiving sheet 21 that is in contact with the thermal head 51, even if an expensive heat-resistant resin sheet is used as the base sheet 22 to prevent wrinkles due to heat and mechanical stress in the printer, Since the amount of consumption of the dye receiving sheet 21 in one image formation is 1/3 to 1/4 of the amount of consumption of the dye transfer sheet 11, the increase in the cost in thermal transfer image formation is significantly larger than in the conventional image forming method. Can be reduced.

FIGS. 2 and 3 show another example of the thermal transfer image forming method of the present invention. 2 is the same as the state shown in FIG. 1 except that a dye image receiving sheet 31 is used instead of the dye image receiving sheet 21, and the dye transfer sheet, platen roller and thermal head are denoted by the same numbers. I have. Dye receiving sheet 31 in FIG.
Has a base sheet 32 and a dye receiving layer 34 formed on one surface of the base sheet 32 with a release layer 33 interposed therebetween. In the thermal transfer image forming method of the present invention shown in FIGS. 2 and 3, the thermal head 51 is in contact with the base sheet 32 of the dye receiving sheet 31, and the base sheet 32 of the dye receiving sheet 31 is in contact with the thermal head 51. From the dye layer 13 of the dye transfer sheet 11, the dye is transferred to the dye receiving layer 34 of the dye image receiving sheet 31 to form an image. Thereafter, as shown in FIG. 3, the transfer target 61 is supplied, and the transfer target 61 is pressed by the platen roller 41 in the direction of the dye image receiving sheet 31, and is superposed on the dye receiving layer 34 on which an image is formed. . Then, the base sheet 32 of the dye receiving sheet 31
The thermal energy is applied from the side by the thermal head 51, and the dye receiving layer 34 is peeled off from the base sheet 32 together with the release layer 33 and transferred to the transfer receiving body 61, and the transfer receiving body 6
1, an image is formed.

The dye image receiving sheet 31 used in the thermal transfer image forming method comprises a base sheet 32 and a dye receiving layer 34.
And a dye receiving layer 3
It is the same as the dye image receiving sheet 21 described above, except that it is necessary to form the sheet 4 from a transparent resin.

The release layer 33 of the dye receiving sheet 31 is formed of a release agent such as waxes, silicone wax, silicone resin, fluororesin, and acrylic resin. Also,
When it is desirable that the image transferred and formed on the transfer receiving body 61 is matte, various types of particles are contained in the release layer 33, or the base sheet on which the surface on the release layer 33 formation side is matted Should be used. When the base sheet 32 of the dye receiving sheet 31 has an appropriate peeling property, the peeling layer 33 is unnecessary.

Now, the present invention will be described in further detail with reference to experimental examples. (Experimental Example 1) First, a blue, yellow and red dye layer ink having the following composition was dried and applied in the order of repetition on the surface of a 6 μm-thick polyester resin sheet (Lumirror manufactured by Toray Industries, Inc.). Was applied in an A4 size by a bar coater in such a manner as to be 1 g / m ² and dried to prepare a dye transfer sheet.

Ink composition for dye layer / dispersed dye (Kayaset Blue 714 manufactured by Nippon Kayaku Co., Ltd.) 4 parts by weight Ethyl hydroxycellulose (manufactured by Hercules) 5 parts by weight Methyl ethyl ketone / toluene (weight ratio 1/1) 1) 80 parts by weight Dioxane 10 parts by weight In addition, the yellow dye layer ink uses a yellow disperse dye (Bayer Macrolex Yellow 6G) as a disperse dye, and the red dye layer ink uses Magenta disperse dye (CI Disperse Re
d 60).

A 6 μm-thick polyethylene naphthalate resin sheet (Teonex, manufactured by Teijin Limited) is coated with a coating solution for a dye-receiving layer having the following composition on a surface to give a dry coating amount of 2 g / m ^2. And then temporarily dried with a drier, and then dried in a 100 ° C oven for 30 minutes.
After drying for a minute, a dye receiving layer is formed, and a silicone oil (Shin-Etsu Chemical Co., Ltd.)
X-41 4003A) was dropped with a dropper, spread over the entire surface to form a back layer, and a dye receiving sheet (No. 1) was prepared.

Composition of the coating solution for the dye receiving layer : vinyl chloride / vinyl acetate copolymer (1000AS, manufactured by Denki Kagaku) 100 parts by weight Epoxy-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by weight Amino-modified silicone (KS-343 manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by weight Methyl ethyl ketone / toluene (weight ratio 1/1) 400 parts by weight Next, the dye layer of the above dye transfer sheet And the dye receiving layer of the dye receiving sheet (No. 1) are overlapped so that they are in contact with each other, and according to the present invention, a thermal head is used from the dye receiving sheet side under the following conditions (high-energy high-speed printing conditions). A full color image was formed on the dye receiving layer of the dye receiving sheet (No. 1).

Thermal transfer conditions • Output: 2 W / dot • Pulse width: 1 msec. • Dot density: 6 dots / mm As Comparative Example 1, a 6 μm thick polyester resin sheet (Lumirror manufactured by Toray Industries, Inc.) was used. A dye receiving sheet (No. 2) was prepared in the same manner as the dye receiving sheet (No. 1). Then, the dye layer of the dye transfer sheet and the dye receiving layer of the dye image receiving sheet (No. 2) are overlapped with each other so as to be in contact with each other, and a thermal head is applied from the dye transfer sheet side according to a conventional image forming method. A full color image was formed on the dye receiving layer of the dye receiving sheet (No. 2) under the same conditions as above.

As Comparative Example 2, a 6 μm thick polyethylene naphthalate resin sheet (Teonex, manufactured by Teijin Limited) was used to prepare a dye transfer sheet in the same manner as the above dye transfer sheet. Then, this dye transfer sheet and Comparative Example 1
In the same manner as in Comparative Example 1, a full-color image was formed in the same manner as in Comparative Example 1 so that the dye-receiving layer of the same dye-receiving sheet (No. 2) as used in Example 1 was in contact with the two.

The image formed on the dye receiving layer of the dye receiving sheet (No. 1) according to the present invention and the image formed on the dye receiving layer of the dye receiving sheet (No. 2) by a conventional image forming method. The image quality and abrasion resistance of Comparative Examples 1 and 2 were evaluated, and the results are shown in Table 1 below.

[0036]

[Table 1]

As shown in Table 1, it was confirmed that the image formed according to the present invention had the same quality as the image formed according to the conventional image forming method. Also,
The occurrence of print wrinkles was able to be suppressed while minimizing material cost increase. Furthermore, the image formed according to the present invention was found to have improved abrasion resistance. (Experimental example 2) Coating liquid for release layer • Polymethyl methacrylate resin (BR-85, manufactured by Mitsubishi Rayon Co., Ltd.) 100 parts by weight Methyl ethyl ketone / toluene (weight ratio 1/1) 400 parts by weight Thickness 6 μm Polyester resin sheet (made by Toray Industries, Inc.)
Lmirror) was coated with a coating liquid for a release layer having the above composition by a bar coater so that the dry coating amount was 2 g / m ² , dried, and then used on this release layer in Experimental Example 1. The same coating solution for the dye receiving layer is dried at a coating amount of 2 g / m ^2.
Is applied with a bar coater and temporarily dried with a drier, dried in an oven at 100 ° C. for 30 minutes to form a dye-receiving layer, and a silicone oil (Shin-Etsu Chemical Co., Ltd.) Made X-41 400
After a few drops of 3A) were dropped with a dropper, it was spread over the entire surface to form a back layer to prepare a dye image-receiving sheet (No. 3).

Next, the dye receiving layer of the above dye receiving sheet (No. 3) and the dye layer of the same dye transfer sheet used in Experimental Example 1 were overlapped so that they abut each other. A full-color image was formed on the dye receiving layer of the dye receiving sheet (No. 3) under the same conditions as in Experimental Example 1 using a thermal head from the dye receiving sheet side in accordance with the above.

Thereafter, the postcard as the transfer object is superimposed on the dye receiving layer of the dye receiving sheet (No. 3) on which an image is formed, and the same thermal head is used from the dye receiving sheet side according to the present invention. The dye receiving layer of the dye receiving sheet (No. 3) was transferred onto a postcard under the following conditions.

Thermal transfer conditions • Output: 0.3 W / dot • Pulse width: 8 msec. • Dot density: 6 dots / mm For comparison, a polyester resin sheet (Lumirror, manufactured by Toray Industries, Inc.) having a thickness of 25 μm was used. Is a dye receiving sheet (No. 4) in the same manner as the above dye receiving sheet (No. 3).
It was created. Then, the same dye layer of the dye transfer sheet as used in Experimental Example 1 and the dye receiving layer of the dye image receiving sheet (No. 4) were overlapped so that they were in contact with each other. Using a thermal head from the transfer sheet side, a full-color image was formed on the dye receiving layer of the dye receiving sheet (No. 4) under the same conditions.

Thereafter, the postcard as the transfer object is superimposed on the dye receiving layer of the dye receiving sheet (No. 4) on which an image is formed, and another thermal head is used from the dye receiving sheet side according to the present invention. The dye receiving layer of the dye receiving sheet (No. 4) was transferred onto a postcard.

An image formed on a postcard using the dye receiving sheet (No. 3) according to the present invention, and an image formed on a postcard using the dye receiving sheet (No. 4) by a conventional image forming method Was evaluated for image quality and durability, and the results are shown in Table 2 below.

[0043]

[Table 2]

As shown in Table 2, it was confirmed that the image formed according to the present invention had the same quality as the image formed according to the conventional image forming method. Also,
It was confirmed that the image formed according to the present invention had high durability. Further, since the printer used in the image forming method of the present invention has one thermal head, the printer can be downsized.

[0045]

As described above in detail, according to the present invention, heat energy is applied from the base sheet side of the dye receiving sheet, and the dye is transferred from the dye layer of the dye transfer sheet onto the dye receiving layer of the dye receiving sheet. Since the image is transferred and formed, it is not necessary to adjust the stress distribution of the complicated transfer mechanism of the printer, and it is not necessary to use an expensive heat-resistant resin sheet as a base sheet of the dye transfer sheet having a large amount of consumption. Since the heating direction at the time of image formation and the heating direction at the time of transfer of the receiving layer are the same, only one thermal head can be mounted on the printer, and the printer can be downsized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a thermal transfer image forming method of the present invention.

FIG. 2 is a diagram illustrating another example of the thermal transfer image forming method of the present invention.

FIG. 3 is a view showing another example of the thermal transfer image forming method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Dye transfer sheet 12 ... Base sheet 13 ... Dye layer 21, 31 ... Dye image receiving sheet 22, 32 ... Base sheet 23, 34 ... Dye receiving layer 33 ... Release layer 41 ... Platen roller 51 ... Thermal head

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-53-108511 (JP, A) JP-A-4-133793 (JP, A) JP-A-4-156385 (JP, A) JP-A-4- 314592 (JP, A) JP-A-5-42776 (JP, A) JP-A-1-160680 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5 / 38-5 / 40 B41J 2/32-2/38

Claims (1)

(57) [Claims] 1. A dye transfer sheet comprising a base sheet and a dye layer formed on one surface of the base sheet, and a dye formed releasably on the base sheet and one surface of the base sheet. A dye image-receiving sheet having a receiving layer, the dye layer and the dye receiving layer are overlapped so as to be in contact with each other,
Samaruhe from the substrate sheet side of said dye image-receiving sheet
An image is formed on the dye receiving layer by applying thermal energy to the thermal head used for the image formation from the base sheet side of the dye image receiving sheet.
And applying heat energy again to transfer the dye-receiving layer to a transfer-receiving member.