JP2004284310A - Image forming method using ink jet and thermal transfer film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method using ink jet, by which an ink jet recording image can be positively formed on the surface of a recording medium in a few processes, the formed image can automatically be protected from scratches or water and which can be completed without being subjected to a special process such as deburring or the like. <P>SOLUTION: A reversed image is formed using the ink jet recording method on the ink receiving surface of a thermal transfer film in which a transparent protective layer and the ink receiving layer are laminated on the surface of the support. After that, the surface of a medium to be recorded is made to face the ink receiving layer to heat/pressurize the thermal transfer film to thermally press bond the transparent protective layer and the ink receiving layer to the surface of the medium to be recorded. After the transparent protective layer and the ink receiving layer are cured, the support of the thermal transfer film is released from the medium to be recorded. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for recording an image on the surface of a recording medium, and more particularly, to a method for forming an image on the surface of a hard resin card using an ink jet and a material used for the method.
[0002]
[Background Art]
It is well known that the ink jet recording method is being applied to various image recording fields because of its features such as good image quality, high-speed recording, easy acquisition of a large screen, and low cost.
By the way, in the ink jet recording method, in order to obtain a high quality image, a dedicated recording medium coated with an ink receiving layer is required, so that the surface of the unprocessed hard resin card used for various certification cards and the like is required. No image can be formed.
[0003]
For this reason, conventionally, a method in which an ink receiving layer is transferred and adhered to the surface of a hard resin card prior to recording by an inkjet head has been proposed in Japanese Patent Application Laid-Open No. 2002-283713.
That is, this transfer / recording method uses an intermediate medium provided with an ink receiving layer and an adhesive layer on the surface of a thermal transfer film support. Prior to recording by an ink jet head, the ink receiving layer of the intermediate medium is hard resin The image is transferred and adhered to the surface of a card (certification card), and thereafter, an image is formed on the surface of the transferred ink receiving layer.
[0004]
[Problems to be solved by the invention]
However, according to this transfer / recording method, a high-quality image can be formed on the surface of the hard resin card to which the ink receiving layer has been transferred. The resulting image cannot be protected from scratches and water.
For this reason, in the above-described image forming method using an intermediate medium, although a transparent film having a protective function is laminated on the surface of the hard resin card after image recording, the hard resin card is added by adding the protective transparent film. Separate processes such as deburring of the protruding transparent film and final punching of the plastic card are required, and strict control of the adhesion state of the protective transparent film to be laminated becomes a problem.
[0005]
The object of the present invention is to not only reliably form an ink jet recorded image on the surface of a recording medium in a few steps, but also to reduce the formed image in consideration of the actual situation of image recording on a conventional hard resin card as described above. An object of the present invention is to provide a method for forming an ink-jet image which is automatically protected from scratches, water and the like, and can be completed without a special step such as deburring, and a material used for the method.
[0006]
[Means for Solving the Problems]
In order to achieve this object, the present invention provides a method for forming a reverse image on an ink receiving layer surface of a thermal transfer film in which a transparent protective layer and an ink receiving layer are laminated on the surface of a support using an inkjet recording method, The transparent protective layer and the ink receiving layer are thermocompression-bonded to the surface of the recording medium by heating and pressing the thermal transfer film with the surface of the recording medium facing the receiving layer, and after the solidification transfer of the transparent protective layer and the ink receiving layer, The present invention proposes an inkjet image forming method for peeling a support of a thermal transfer film from a recording medium.
[0007]
In the description of the preferred embodiments of the invention described below,
A thermal transfer film for use in a method of manufacturing a certification card including a support, a transparent protective layer that can be peeled off from the support and has excellent scratch resistance and water resistance, and an ink receiving layer that receives inkjet ink will be described.
[0008]
The transparent protective layer is made of a resin having excellent transparency, abrasion resistance and water resistance. It can consist of a mixture of more than one species.
[0009]
The transparent protective layer for effectively protecting the ink receiving layer and suppressing the generation of burrs at the time of transfer preferably has a thickness of 1 to 30 μm. Is insufficient, and if it is thicker than this, burrs are likely to occur during transfer to the recording medium.
[0010]
And, the ink receiving layer in the present invention is preferably composed of a porous film containing inorganic fine particles and a binder for ink absorption and reduction of burrs at the time of transfer.
Examples of the inorganic particles of the ink receiving layer include silica, alumina, calcium carbonate, barium sulfate, zinc oxide, and titanium oxide.
[0011]
The binder of the ink receiving layer is preferably a resin having a Tg of 50 to 200 ° C. in order to improve the adhesion to a recording medium as a recording medium, and a hydrophilic resin in order to improve the ink absorption. It is better to be.
[0012]
Examples of the binder resin for the ink receiving layer include a cellulose resin, a polyvinyl alcohol resin, a polyvinyl acetate resin, a hydrophilic natural polymer (sodium alginate, gum arabic, gelatin, casein, dextrin, etc.). These resins may be used alone or in combination of two or more.
[0013]
The thickness of the ink receiving layer is preferably from 10 to 100 [mu] m in order to hold an image formed by the ink jet head and to suppress the occurrence of burrs during transfer. In other words, when the thickness of the ink receiving layer is smaller than this, the ink absorbency decreases, so that an image formed by the inkjet head cannot be held, and the ink dries slowly. If the thickness is larger than this, burrs are likely to occur during transfer.
[0014]
As the support of the thermal transfer film used in the present invention, a known support can be used according to the intended use as long as it can be peeled off from the transparent protective layer. That is, polyester resin, polyolefin resin, cellulose acetate resin, acrylic resin, polycarbonate resin, polyvinyl chloride resin, polyamide resin, polyimide resin, cellophane, celluloid, resin-coated paper, and the like.
[0015]
The above-mentioned resin constituting the transparent protective layer and the binder contained in the ink receiving layer may contain various additives as necessary, for example, stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), antistatic agents, It may contain a flame retardant, a lubricant, an anti-blocking agent, a coloring agent, an antifoaming agent, a coating improver, a thickener, and the like.
[0016]
The thermal transfer film according to the present invention can be manufactured by sequentially laminating a transparent protective layer releasable from the support on one surface of the support and a porous ink receiving layer containing inorganic fine particles and a binder. Each coating agent that becomes the transparent protective layer and the ink receiving layer can be applied to the surface of the support using, for example, a roll coder, an air knife coater, a blade coater, a rod coater, a bar coater, a comma coater, or a gravure coater. The drying temperature of these coating films is preferably from 50 to 150 ° C, more preferably from 80 to 130 ° C.
[0017]
In the following description of embodiments and examples of the present invention, a hard resin card (plastic sheet) is exemplified as a recording medium, but the present invention is not limited to this hard resin card. .
[0018]
Embodiment
FIG. 1 shows one embodiment of the ink jet image forming method of the present invention. On the back surface of the thermal transfer film A, that is, on the side of the ink receiving layer a3, an image in which the left and right are reversed using the ink jet head 1 is formed by scanning. The thermal transfer film A is sent to the thermal transfer station 4 by the guide rollers 2 and 3, where the thermal transfer film A is superposed on the hard resin card B (plastic sheet) which is supplied synchronously, and is pressed against the holding plate 5 and the heating plate. By pressing the roller 6, the image, the ink receiving layer a3, and the transparent protective layer a2 are thermally welded to the surface of the hard resin card B as the recording medium.
[0019]
As shown in FIG. 2, on the surface of the thermal transfer film A according to the present invention, on the surface of the film-like support a1, there is provided a transparent protective layer a2 which can be peeled off from the support a1 and has excellent scratch resistance and water resistance. An ink receiving layer a3 for receiving the inkjet ink is applied.
[0020]
Then, after the transparent protective layer a2 and the ink receiving layer a3 are solidified, the support a1 of the thermal transfer film A is separated from the hard resin card B by the deflecting roller 7, and the transparent protective layer a2 is separated from the support a1 by this separating movement. Is done.
At the time of this peeling, the transparent protective layer a2 and the ink receiving layer a3 corresponding to the surface of the hard resin card B that have been subjected to the pressure and heating of the heating roller 6 remain on the surface of the hard resin card B, but the transparent protective layer a2 is hard resin. Since it is easily broken at the periphery of the card B, no "burrs" remain at the periphery of the hard resin card B.
[0021]
【Example】
Example 1
An acrylic resin (Mitsubishi Rayon acrylic resin, Dianal FR-4867) as a transparent protective layer a2 was formed to a thickness of 5 μm on the corona-treated surface of a 38 μm PET film (Toyobo, Ester Film E5100) as a recording medium. It was applied with a doctor bar and dried at a temperature of 110 ° C. Thereafter, as the ink receiving layer a3, a resin for the ink receiving layer a3 (Takamatsu Oil & Fat, MZ-479) in which fine silica and polyurethane resin were mixed was applied with a doctor bar to a dry thickness of 25 μm.
[0022]
Next, a reverse image of a desired image was formed on the ink receiving layer a3 using the commercially available aqueous inkjet head 1, and a clear image without ink overflow or bleeding could be formed.
[0023]
Next, the ink receiving layer a3 on which the image has been formed and the hard resin card B (PET-G, 0.28 mm thick) as a recording medium face each other, and are heated and pressed at a temperature of 120 ° C. to form the support a1. Peeled off. On the hard resin card B, the ink jet image was uniformly transferred without any transfer omission and burrs. The transferred image had no image disturbance such as ink overflow or bleeding, and had good adhesion to the hard resin card B as a recording medium. Further, a transparent protective layer a2 is provided on the surface of the transferred image, and the image is not destroyed even if the surface is rubbed. The water resistance was also good.
[0024]
Example 2
Instead of the 38 μm PET film in Example 1, a resin coated paper obtained by applying a polyurethane resin (Takamatsu Oil, NS-310X) to a 130 μm thick paper sheet (special paper, MR-T150) was used as a recording medium. However, as in the case of Example 1, the image was successfully transferred to the hard resin card B as the recording medium.
[0025]
Comparative Example 1
In Example 1, the same operation was performed without providing the transparent protective layer a2, but the image transferred to the recording medium was easily destroyed when the surface was rubbed. In addition, contact with water caused image bleeding.
[0026]
Comparative Example 2
In Example 1, when the same operation was performed using only the polyurethane resin without mixing the fine particle silica into the ink receiving layer a3, burrs were generated at the time of transfer.
[0027]
Comparative Example 3
In Example 1, when the thickness of the transparent protective layer a2 was set to 40 μm and the same operation was performed, burrs were generated at the time of transfer.
[0028]
【The invention's effect】
As is apparent from the above description, according to the present invention, a clear image free of ink overflow or bleeding can be formed in a single transfer step on a recording medium that has not been processed for inkjet recording. In addition, a transparent protective layer for protecting an image can be simultaneously formed on the surface of the recording medium.
Further, according to the present invention, the transferred inkjet image maintains a good fixing state, does not generate burrs at the time of peeling of the thermal transfer film, and uses an inkjet-based image forming method and a thermal transfer film formed at low cost. Can be provided.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of an inkjet image forming apparatus according to the present invention.
FIG. 2 is an enlarged sectional view of a main part of a thermal transfer film A used in the present invention.
[Explanation of symbols]
Reference Signs List A Thermal transfer film a1 Support a2 Transparent protective layer a3 Ink receiving layer 1 Ink jet head 4 Thermal transfer station 5 Press plate 6 Heat roller 7 Warp roller

Claims (5)

After forming a reverse image using an ink jet recording method on the surface of the ink receiving layer of the thermal transfer film in which the transparent protective layer and the ink receiving layer are laminated on the surface of the support, the surface of the recording medium faces the ink receiving layer. The transparent protective layer and the ink receiving layer are thermocompression-bonded to the surface of the recording medium by heating and pressing the thermal transfer film to remove the support of the thermal transfer film from the recording medium after the solidification and transfer of the transparent protective layer and the ink receiving layer. An inkjet image forming method comprising: The thermal transfer film used in the inkjet image forming method according to claim 1, comprising a support, a transparent protective layer that can be peeled off from the support and has excellent scratch resistance and water resistance, and an ink receiving layer that receives the inkjet ink. 3. The thermal transfer film according to claim 2, wherein the transparent protective layer is made of a resin having excellent transparency, abrasion resistance and water resistance, and has a thickness of 1 to 30 [mu] m. 3. The thermal transfer film according to claim 2, wherein the ink receiving layer is formed of a porous film containing inorganic fine particles and a binder, and the binder has a Tg of 50 to 200 [deg.] C. and a thickness of 10 to 100 [mu] m. 2. The inkjet image forming method according to claim 1, wherein the recording medium is a hard resin card.

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